The Theory of Self-Evidence in Islamic Philosophy

By Abdul Husayn Khusro-Panah. I began translating this paper originally in 2016, in the city of Qom, but never got around to finishing it. I recently found the motivation to finish the translation, as I am currently teaching a teacher training module called Logic for Educators. This paper was originally published in 2006 in an academic journal called Zehn.

Foundationalism is one theory and a response to the problem of justification. Since knowledge is defined as justified true belief, justification must be counted as one of the pillars of epistemology. In other words, any claim to knowledge, for example, the assertion that “A is B”, must be capable of being justified; that is, one must be able to present sufficient and necessary reasons to establish it. Thus, in addition to truth, a knower must seek evidential truth and transmit adequate reasons to others so that they, too, may accept it. Epistemologists, in discussing justification or the provision of necessary and sufficient reasons for knowledge, have proposed at least three theories: foundationalism, coherentism, and pragmatism. All of these theories seek to explain true knowledge, knowledge that, at least hypothetically, corresponds to nafs al-amr (the objective state of affairs), and that can be established through sufficient rational evidence in the context of proof and justification.

The three aforementioned theories differ in how they explain the realization of this process.

The theory of foundationalism is the simplest response to the question of justification. It was initially proposed by the sages of ancient Greece and later reinforced by philosophers, logicians, and Muslim theologians. Foundationalism has various interpretations; however, the traditional foundationalism of Muslim philosophers is grounded in the theory of self-evident knowledge (badāhah). According to this view, human beliefs and cognitions are divided into two categories: basic or foundational beliefs, and inferential beliefs. Foundational beliefs are those that possess intrinsic justification; they do not require further proof. These include evident cognitions whose justification lies either in the mere conception of the subject and predicate, or in a judgment whose truth is affirmed immediately – without effort or mediation – once it reaches the level of necessity.

These primary and secondary self-evident propositions enable the knower to complete the process of establishing truth. Regarding the origin of self-evident beliefs, the discussion centers on whether they are innate to human nature, acquired through sense perception, or attained through the gradual perfection of the material intellect and the rational faculty. Numerous analyses have been offered on this question. Given the close relationship between foundationalism and the theory of self-evidence, in this context, the theory of self-evidence as understood in Islamic philosophy is examined.

Background of the Theory of Self-Evidence

The criterion of knowledge is among the oldest topics in epistemology, and Plato and Aristotle also addressed it in their works. Regarding what constitutes the criterion of knowledge, various epistemological approaches have been proposed.

Plato regarded sensory cognitions as lacking epistemic value and held that there is no criterion by which true sensory knowledge can be distinguished from false. He considered only intellectual cognitions to be worthy of knowledge and believed in the existence of a kind of innate intellectual information, as a remembrance of life prior to this worldly existence.
Rationalists, by emphasizing reason or intellect, considered it the most effective factor in attaining certain knowledge. Many of them, however, acknowledged that sensory experience initiates cognition and recognized the usefulness of experience and observation, yet they limited their effect to the level of an initial stimulus or a preliminary movement for grasping self-evident principles and criteria, principles which they regarded as innate to human nature. On this basis, they held that the mind, supported by certain self-evident truths, is capable of inferential reasoning for the indefinite expansion of knowledge. In practice, they believed in the existence of innate and non-empirical self-evident cognitions that are not acquired through external observation or empirical investigation and which constitute some of the most fundamental beliefs of rational thinkers.
In contrast, another group considered only sensory and experiential knowledge derived from the external world to be epistemically valid and became known as empiricists. They denied prior (a priori) knowledge and did not consider any event to be known in advance; rather, they believed that every occurrence requires causal explanation insofar as it is placed within the framework of teleological judgment. According to them, such propositions do not provide central truths about things or realities; rather, it is experience that reports reality.

This line of thought can also be traced in Aristotle’s works. Aristotle held that knowledge and cognition rest upon self-evident principles, and he considered the examination of self-evident principles to be among the tasks of philosophy. Since these self-evident principles are assumed to apply to all beings in general, examining them also falls under the task of that discipline which investigates being qua being (ma huwa mawjud). Because this discipline is a form of knowledge that transcends natural science, reflection on these self-evident principles likewise constitutes a philosophical inquiry into being qua being.

Aristotle regarded the principle of non-contradiction as the most fundamental principle. By this, he meant that one thing cannot both be and not be at the same time and in the same respect. This principle is the most fundamental of all principles. He continues by stating that to demand proof for everything leads to an infinite regress; therefore, demonstrative principles cannot themselves be proven.

With respect to defining first principles, Aristotle states: “That which is known first is called a principle.” This beginning is also referred to as the starting point or the principle of the thing, such as the premises or axioms employed in demonstration.

In any case, Aristotle was the first to explicitly draw attention to self-evident principles, especially among philosophers before Thales, such as Empedocles, Pythagoras, Parmenides, and others, although no independent works from them on this topic have survived. Perhaps this is because the works of these thinkers are no longer extant, and their views can mostly be traced through the writings of Aristotle and Plato. It is also possible that Aristotle, during his travels with Alexander to regions such as Egypt, Babylon, and Iran, encountered this idea and subsequently benefited from earlier traditions.

Nevertheless, references to self-evident principles can also be found in Plato’s works. However, Plato’s treatment of the issue, unlike Aristotle’s explicit and systematic discussion, appears in a more allusive and indirect manner. Aristotle, in the Metaphysics and Physics, under chapters devoted to philosophy as the knowledge of truth or the cognition of reality, despite the difficulty of the subject, holds that knowledge of truth and access to the realm of realities is possible. He regards skepticism as a kind of confusion and believes that inquiry must begin with self-evident principles.

From one perspective, knowing the truth is easy, and from another perspective, it is difficult. No one can entirely fail to reach the truth, yet no one can fully grasp it either. Human beings do not err entirely in their attempt to know; rather, everyone says something about nature, and each person may reach a portion of the truth or come close to it. When these partial insights are brought together, they collectively attain a significant epistemic value.

He illustrates this with a well-known analogy: finding the door of a house is easy, but entering it may be difficult. Likewise, we are capable of grasping some portion of the truth, but not all of it at once. The difficulty arises not from the objects themselves, but from us, because the human intellect, when confronted with matters that are extremely evident in nature, is like the eyes of bats before daylight. This is why philosophy is called the knowledge of truth: its aim is theoretical cognition of truth and practical understanding of reality.

Since these self-evident principles apply universally to all beings, their investigation falls under the task of the science that studies being qua being. Because this science transcends natural science, reflection on these self-evident principles is itself a philosophical inquiry.

Among these self-evident principles is the principle of non-contradiction, which we described as the most fundamental of all principles. It states that a thing cannot both be and not be at the same time and in the same respect. This is the most fundamental of all principles, because one cannot offer proof for everything; otherwise, an infinite regress would ensue, and thus demonstrative principles would not be possible.

The theory of self-evidence, from the time of Plato – clearly reflected in Aristotle’s works – continued its development in philosophy through Descartes, Spinoza, Leibniz, and Kant down to the modern era. Muslim thinkers likewise accepted, in accordance with Aristotle’s view, the existence of self-evident conceptions and judgments as basic data of knowledge.

Descartes regarded three principles as innate and self-evident prior cognitions: (1) the impossibility that something both exists and does not exist at the same time; (2) that nothing can be the efficient cause of itself; and (3) that human beings possess free will.

Moreover, Descartes considered certain conceptual notions, such as God, the soul, extension, and form, to be self-evident concepts. Kant, in addition to the twelve categories and the forms of sensibility (space and time), also counted the principle of causality among self-evident principles. According to him, every phenomenon necessarily occurs by means of a cause and in accordance with fixed and determinate laws.

Some European thinkers, in their effort to undermine the credibility of prior and self-evident knowledge, have argued that the principle of causality and the dependence of effects upon causes and fixed laws is incompatible with human freedom. They claim that Descartes enumerates three axioms and identifies the third, human freedom, as a truth that must be accepted as primary and self-evident, even though it is vulnerable to doubt, since human knowledge is fallible and subject to error at all times.

In addition, they argue that the notion of rational self-evidence conflicts with the fourth axiom attributed to Kant, according to which the mind regards causality as valid prior to experience and before appealing to empirical testimony.

In reality, this difficulty arises from inattention to the proper meaning of causality and free will, and from an incomplete and imprecise division of causality into complete and incomplete causes, as well as from neglecting the role of volition as a component of causation in voluntary actions. Descartes and Kant, in addition to philosophical self-evident principles, also point to mathematical self-evident judgments. As examples, they cite the following axioms as self-evident principles:

a. The sum of the internal angles of a triangle is 180 degrees.
b. The essence of everything possesses both genus and differentia.

Kant, however, refers to the following three principles:

a. Space has three dimensions.
b. A straight line is the shortest distance between two points.
c. In changes of accidents and events, the substance remains constant, and nothing is added to or subtracted from the quantity of substance in nature.

It is noteworthy that philosophers, despite their disagreements concerning the instances of prior knowledge and self-evident propositions, agree that there exist cognitions independent of external experience, which may be termed non-empirical knowledge. Such cognitions are not obtained directly from experience, but rather are acquired through mental activity and rational processes. These abstract cognitions may even be more reliable than knowledge of the material world.

Among self-evident principles upon which there has never been disagreement among philosophers is the principle of the impossibility of contradiction, which is identical with the principle of identity. Some philosophers, however, in opposition to self-evidence, have attempted to cast doubt upon this principle as well.

Definition of Self-Evident Propositions

In the rational traditions of Islam, the term badāhah (self-evidence) was first employed by Ibn Sina (Avicenna) in his commentary on Ishārāt. After him, Nasīr al-Dīn Ṭūsī and others made use of this term, and it eventually became part of the common vocabulary of scholars, sages, and logicians.

In philosophical, logical, and even mystical works, numerous expressions have been used for self-evident propositions, including: necessities (ḍarūriyyāt), innate propositions (fiṭriyyāt), primary propositions (awwaliyyāt), self-evident axioms, principles of the sciences, common notions, first intelligibles, primary conceptions, primary assents, and so forth. In contrast, theoretical propositions and non-self-evident propositions have been referred to as acquired propositions, secondary intelligibles, information obtained through reasoning and inference, and the like.

In logic, various definitions of self-evident propositions have been proposed. Despite the diversity of these definitions, they are not mutually exclusive. Rather, some definitions are more precise than others, since the concept of self-evidence belongs to the category of secondary intelligibles, which does not possess a genus and differentia. Consequently, multiple definitions may be given for it, each highlighting a particular aspect of its necessary attributes. For this reason, all such definitions can be regarded as correct.

ʿAḍud al-Dīn al-Ījī, following earlier theologians, divides knowledge into necessary and acquired. He defines necessary knowledge as that which “the soul necessarily possesses, such that it cannot but assent to it”.¹

This definition is not incorrect, but it is incomplete. Necessary knowledge is not confined to formal logical knowledge; rather, it includes both matter and form. In other words, epistemological laws governing both the material and formal aspects of knowledge must be observed. Although all knowledge is, in one sense, acquired, since it is realized only once its conditions are fulfilled, it should not be concluded that every piece of knowledge lacks the distinctive feature of self-evidence.

Self-evidence, in its technical sense, is not restricted to axioms alone; it also encompasses theoretical certainties. However, it is often said that causes appear evident to the human mind when they are reduced to their reasons, and that theoretical certainties become evident once they are reduced to self-evident premises. Even so, this does not mean that every theoretical assent becomes self-evident merely by being reduced to reasons, because sometimes causes do not satisfy the criteria of true causality.

For example, one may argue and reason that a particular individual is a thief, but due to personal interests or psychological biases, the soul may refuse to assent to that conclusion. Similarly, individual, collective, partisan, or emotional inclinations may distort the meaning of evidence and impede assent. However, primary self-evident propositions are not affected by such inclinations. This characteristic is unique to self-evident propositions: many of our cognitions are influenced by causes, and underlying motives alter many beliefs, but primary self-evident propositions are neither generated by causes nor affected by ulterior motives.

Al-Ījī defines self-evident knowledge as: “that which cannot be acquired”². This definition, unlike his earlier theological definition, emphasizes the non-acquirability of self-evident knowledge rather than the soul’s inability to withhold assent. In other words, self-evident knowledge is not obtained through inference, reasoning, or acquisition. This definition is essentially correct, although a more precise formulation can still be offered.

Ibn Sīnā, in al-Ishārāt, refers to self-evident knowledge as a judgment that, when one attends to it, is immediately grasped, such that the intellect perceives it as true in reality and in conformity with what lies outside the mind³. In other words, such a proposition possesses both intuitive certainty and correspondence with external reality.

This definition, too, is valid, though once again somewhat general, because it includes certain theoretical judgments. That is, it encompasses judgments whose material and form are such that their premises are already evident, and whose correspondence with reality is also evident. This feature, however, is not exclusive to primary self-evident propositions.

Islamic sages have also defined self-evident knowledge as knowledge that is universally acknowledged. Nevertheless, although many self-evident propositions are indeed accepted by all rational agents, this criterion does not provide a precise standard for identifying self-evidence.

Despite these varying approaches, the well-known and widely accepted definition among Islamic sages, mentioned by many of them, is the following: self-evident or necessary knowledge is knowledge that does not require acquisition or inference. In other words, it is knowledge that arises immediately after the conception of the subject and predicate, without the need for experience, reasoning, or any mediating process. Based on this immediate cognition, a definitive judgment is issued regarding the relation between the two.

In general, for innate and self-evident cognitions, several meanings have been mentioned in philosophical terminology:

Cognitions that are identical for all minds, such that there is no difference among them in terms of quantity or quality.
Conceptions and judgments whose acquisition is not dependent upon learning or inference.
Cognitions that exist potentially in every mind, even though they are actualized differently.
Judgments whose assent follows immediately upon themselves; that is, propositions that are grasped with minimal mediation and do not require reflection or intellectual effort.
Cognitions that are intrinsic properties of the intellect and have no need for support from anything external to reason.

The terms innate and self-evident, among Western rationalists such as Descartes and Kant, have been employed in a fifth sense, and this usage has been rejected by empiricists in the West as well as by many Islamic philosophers.

Mullā Ṣadrā, in defining self-evidence, considers two necessary conditions:

The attainment of self-evident knowledge at the beginning of human existence.
The common participation of all human beings in the apprehension of these self-evident truths.

He holds that human beings possess a type of innate self-evident knowledge that is apprehended without need for mediation or proof, and that such knowledge does not require sense perception, experience, or testimony as prerequisites. Rather, the mere conception of the subject and predicate suffices for assent.

He states: “Self-evident knowledge is that knowledge which arises in the soul at the very first moment of reflection, and which all people share equally. These are the primary axioms, and they do not require mediation by any external factor, such as sensation, experience, testimony, or anything else beyond the mere conception of the two terms.”⁴

Scholars of logic and philosophy have divided self-evident propositions into two categories: self-evident conceptions and self-evident judgments. Self-evident conceptions are those universal notions that are not subject to division by genus and differentia, such as the concepts of existence, non-existence, cause, effect, and the like. Of course, common and simple notions – such as primary axioms – are also included among them.

Self-evident judgments, on the other hand, have been classified by these scholars into six categories: primary propositions, sensory propositions, experiential propositions, intuitive propositions, widely accepted propositions, and transmitted propositions⁵.

Self-Evidence: The Basis of Foundationalism

Most Islamic thinkers maintain that, in the domain of conceptions, the origin lies in sense perception and experience, whereas in the domain of judgments, the origin lies in the intellect. That is, the senses initially apprehend sensory forms and perceptual data, and then the intellect, through abstraction, forms universal concepts. These universal concepts subsequently give rise to intellectual judgments, and finally to sensory judgments.

In truth, however, Islamic sages hold that in the domain of judgments, the primary source is the intellect, even though sensory conceptions precede it. This discussion is among the oldest in epistemology and is directly related to the criterion of knowledge. Nevertheless, general perspectives on the criterion of knowledge fall into four major approaches: foundationalism, coherentism, reliabilism, and relativism.

Most rationalist and empiricist philosophers have ultimately arrived at the theory of foundationalism. This theory grounds the justification of knowledge in foundational propositions. It claims that there exist fundamental propositions upon which all other cognitions rest and by reference to which they are measured for correctness and truth.

This theory also responds to the question of how a belief may be justified, or how a piece of knowledge may be shown to be true and in conformity with reality. According to foundationalism, justification proceeds by reducing non-basic cognitions to basic ones. These non-basic cognitions are inferred and derived from foundational propositions, whereas the foundational propositions themselves are self-evident and do not require inference or demonstration.

According to this theory, all knowledge ultimately rests upon self-evident propositions. If a belief is derived—whether directly or indirectly—from self-evident propositions, it is correct; otherwise, it is erroneous. In practice, foundational propositions and self-evident truths serve as the criterion by which genuine knowledge is distinguished from false belief.

There is, however, disagreement regarding the specific instances of these foundational propositions. Foundationalists themselves are divided into rationalists and empiricists, yet all of them share a common conviction: the necessity of grounding knowledge upon self-evident and foundational propositions.

Foundationalists typically argue for the necessity of the existence of foundational propositions as follows: if we deny foundational propositions, then no cognition will be epistemically attainable for us. Inevitably, either we will fall into circularity, or we will be led into an infinite regress. It is, of course, possible that skeptics, especially those inclined toward radical skepticism, might accept this consequence. However, the present claim is not merely rhetorical. Rather, the central issue is to explain where knowledge originates: either knowledge must be self-evident, or it must be derived and inferred from another piece of knowledge. Therefore, the existence of foundational cognitions, independent of the truth of their instances and their justificatory criteria, must be accepted as self-evident.

The Classification of Self-Evident Propositions

In Islamic philosophy, self-evident propositions are divided into two categories: self-evident conceptions and self-evident judgments. Self-evident conceptions are notions that are immediately known and do not require definition; in fact, defining them is essentially impossible, because they are simple and lack genus and differentia. Self-evident judgments, by contrast, are propositions for which the intellect issues a particular judgment without the need for inference or syllogistic reasoning.

This category of self-evident propositions is itself divided into primary and secondary self-evident propositions. Primary self-evident propositions are those that require neither inference nor the formation of a middle term, nor any mediation whatsoever. They do not require observation or experience either. Rather, the mere presentation of the subject and predicate to the intellect suffices for the intellect to issue a decisive judgment.

In secondary self-evident propositions, however, the mere presentation of the subject and predicate is not sufficient for the intellect to issue judgment. Although searching for a middle term is not necessary, some form of attention to sensory experience, inner awareness, or repeated transmission is required to grasp the relation between subject and predicate. Nevertheless, these propositions are still considered self-evident, since they do not belong to the class of theoretical propositions.

Secondary self-evident propositions themselves are not all of the same rank. They differ in the strength and weakness of the connection between subject and predicate⁶.

Accordingly, self-evident propositions have been classified from different perspectives as follows:

Conceptions and judgments
Theoretical and practical
Primary and secondary

Self-Evident Conceptions and Judgments: Theoretical and Practical

Theoretical and Practical Self-Evident Propositions

Conceptions are divided into acquired (kasbī) and necessary (ḍarūrī). Acquired conceptions are those whose formation requires definition through genus and differentia. Every definition by genus and differentia is composed either of a complete definition (ḥadd tāmm) or an incomplete definition (ḥadd nāqiṣ), and both are included under the category of definition.

A complete definition consists of genus and proximate differentia; an incomplete definition consists of genus and remote differentia. A descriptive definition (rasm) also has two forms: a complete description consists of genus and a specific accident, while an incomplete description consists of a specific accident alone or together with another accident.

In contrast, acquired conceptions stand against necessary or self-evident conceptions, which do not require definition by genus and differentia or by description.

Judgments, likewise, are divided into acquired and necessary. Acquired judgments are theoretical judgments that require inference by means of a minor and a major premise. Necessary or self-evident judgments, by contrast, are judgments in which no inference is required.

Primary and Secondary Self-Evident Propositions

As previously noted, the general criterion of self-evidence (whether in conceptions or judgments) is the absence of need for thought and reflection. This lack of need for reflection does not mean the impossibility of reflection; rather, it means that even if reflection and inference are possible, they are not required. That is, a conception or judgment may be self-evident while still being capable of inference and theoretical examination.

On this basis, logicians have divided self-evident propositions into primary and secondary.

Primary self-evident judgments are those that do not require thought or reflection (this is their general criterion), nor are they capable of inference. In other words, primary self-evident propositions are judgments whose denial necessarily presupposes their affirmation, such that any argument offered against them ultimately refers back to them. Therefore, in addition to being free of the need for inference, they are also incapable of inference. An example is the proposition expressing the impossibility of the conjunction of contradictories.

Similarly, primary self-evident conceptions are those simple conceptions that are entirely clear and evident in themselves, require no other conception for their clarification, and have no more general concept above them by which they could be defined. Concepts such as existence and thing may be cited as examples.

By contrast, secondary self-evident judgments are propositions that are clear and evident due to a cause or explanation, yet do not require inference or discursive reasoning, even though they are capable of inference. Examples include experiential propositions.

Likewise, secondary self-evident conceptions are concepts whose conception requires another concept, although they may be defined through more general concepts. For instance, although heat and cold are self-evident, they can nevertheless be defined through more general notions such as intensity and weakness. Similarly, concepts such as being, existence, and causality may be clarified through more general conceptual relations.

Since epistemology and the criterion of knowledge are grounded in judgments and propositions, the discussion of self-evidence focuses primarily on judgments. As noted earlier, secondary self-evident propositions do not require inference, but they are capable of inference, whereas primary self-evident propositions require neither inference nor are they capable of it.

This distinction is of great importance and precision. Ṣadr al-Mutaʾallihīn states: “The acquisition of primary conceptions—such as the concept of existence—and primary judgments—such as the impossibility of the conjunction of affirmation and negation in a single respect—is not possible through acquisition.”⁷

That is, the concept of existence cannot be acquired through definition, nor can the impossibility of the conjunction of contradictories be acquired through inference, because both are self-evident and foundational.

Thus, once self-evidence (whether conceptual or propositional) is neither dependent on definition nor on inference, and is therefore free from discursive reasoning, it is classified as primary self-evidence. Otherwise, if it does not require inference but is nevertheless capable of inference, it is classified as secondary self-evidence.

It should be noted that the division of propositions into self-evident and theoretical, and the division of self-evident propositions into primary and secondary, is based on a rational and exhaustive classification, not an inductive or empirical one. That is because every proposition either requires thought and inference or it does not; and if it does not, then either inference is impossible (primary) or merely unnecessary (secondary).

The Non-Inferability of Primary Axioms

The important question, then, is why primary self-evident propositions are said to be non-inferable. The claim is that self-evident propositions are not inferable, and this is an argument advanced by logicians and philosophers. For example, Ibn Sīnā and Ṣadr al-Mutaʾallihīn have both argued for the non-inferability of primary axioms.

However, the principle of the impossibility of the conjunction of contradictories, even though it is itself non-inferable, can nonetheless be used in argumentation. That is, although such propositions cannot be inferred from prior premises, they can serve as premises in argument. Thus, when we say that “A is self-evident,” and then claim that it is non-inferable, these two claims are not contradictory. The proposition A is self-evident and non-inferable, while the proposition ‘A is self-evident’ is a theoretical judgment and therefore inferable. These are two distinct propositions.

Among the arguments given for the non-inferability of primary self-evident propositions are the following:

If primary self-evident propositions were inferable, they would require premises.
But those premises would themselves either be primary self-evident propositions or non-self-evident propositions. If they were primary self-evident propositions, then their inferential justification would collapse into circularity. And if they were non-self-evident propositions, then their acceptance would itself depend on primary self-evident propositions. Thus, in either case, inferability fails.

For example, in order to establish the principle of the impossibility of the conjunction of contradictories, one would need to assume premises such as: “A cannot both be B and not be B,” or “If A is B, it cannot be not-B.” But this is precisely the same principle under discussion. Hence, any attempt to infer it presupposes it, which is the very definition of circular reasoning.
If primary self-evident propositions were inferable, they would require a middle term.
But in self-evident propositions, the relation between subject and predicate is immediate and essential, not mediated by any external factor. There is no middle term by which the predicate could be linked to the subject, because the connection is intrinsic and direct. Hence, introducing a middle term is impossible in the case of self-evident propositions⁸.
The denial of the principle of the impossibility of contradiction is itself contradictory.
Anyone who denies this principle must either accept absolute skepticism or embrace relativism. But even the skeptic or relativist must implicitly rely on this principle in order to deny it, since denial itself presupposes the distinction between affirmation and negation. Thus, whoever attempts to reject this principle necessarily affirms it in practice. For this reason, the principle is non-inferable.

In summary, the criterion of self-evident propositions is their lack of need for acquisition or inference. In primary self-evident propositions, the predicate is affirmed of the subject immediately and without mediation. Therefore, they are non-inferable and constitute the standard and criterion of truth.

By contrast, many of the propositions that are presented as opposing these axioms are manifestly false. For example, some Marxists claim that “rain comes and then stops; rain comes again and then stops; therefore, rain both exists and does not exist.” This is an obvious confusion, because one of the conditions for the conjunction of contradictories is unity of time and respect, which has been ignored here.

Therefore, all propositions and judgments ultimately rest upon self-evident axioms, and these primary axioms themselves are not inferable.

Ṣadr al-Mutaʾallihīn writes: “All propositions and theoretical judgments ultimately terminate in self-evident propositions, because every proposition requires assent, and this proposition is among the primary assents that does not require another assent.”⁹

The Number of Self-Evident Propositions

In logical and philosophical works, just as there is disagreement concerning the definition of self-evident propositions, there is also disagreement regarding their classification and number. For example, al-Fārābī classifies self-evident propositions into: commonly accepted propositions, observations, sensory data, and first intelligibles¹⁰. Elsewhere, eight types of self-evident propositions are enumerated: observations, primary propositions, intuitions, intuitively evident propositions, conjectures, and theoretical propositions¹¹.

Al-Ījī enumerates eight types of certainties, including: primary propositions, propositions whose middle terms are themselves evident, sensory observations, experiential propositions, intuitive propositions, transmitted propositions, and widely accepted propositions¹². Al-Taftāzānī divides certainties into six categories: primary propositions, observations, intuitions, conjectures, widely accepted propositions, and experiential propositions¹³.

Shaykh al-Ishrāq (Suhrawardī) includes primary propositions, observations, intuitions, and experiential propositions among certainties, while placing conjectures under intuitions, and experiential propositions under intuitions as well¹⁴. Other logicians have likewise discussed the principles of certainties in their works, though with varying enumerations¹⁵.

Although numerous different enumerations are presented in these works, the differences among them are largely superficial. There is no fundamental disagreement concerning what counts as self-evident knowledge. The apparent divergence can be traced to several factors:

Differences in terminology.
Some scholars enumerate fewer categories of certainties by subsuming several types under broader categories. For instance, Shaykh al-Ishrāq defines experiential propositions in a manner that includes both sensory observations and intuitions, by adopting a broader conception of experience—one that encompasses both sense perception and inner awareness. Thus, one reason for disagreement is merely terminological, and such differences should not be exaggerated.
Confusion between certainties and self-evident propositions.
Many logicians classify types of certainties rather than types of self-evident propositions. Later authors sometimes mistakenly assume that all certainties are self-evident, whereas earlier logicians distinguished between certainties that are self-evident and certainties that are theoretical but well-established. In some classifications, logical certainty (yaqīn manṭiqī) and philosophical certainty (yaqīn falsafī) are conflated.

Certainty may be divided, from one perspective, into logical certainty and psychological certainty. Logical certainty is that which can be transmitted and justified through logical inference, even if it is not actually inferred. Psychological certainty, by contrast, is an inner state of conviction that may be personal and subjective. Some individuals—such as practitioners of dialectical theology or rhetoric—may achieve psychological certainty without logical justification. That is, such certainty may be psychologically compelling but logically unsound.

Some logicians (such as Ustād Miṣbāḥ Yazdī in his works on philosophy education) have restricted the category of certainties to those that are logically transmissible and inferentially valid, thereby limiting the number of certainties. Others have expanded the classification to include experiential and intuitive certainties. A third group has further extended the classification by including psychological certainty and even emotive or affective conviction.

Shahīd Ṣadr, in al-Usus al-Manṭiqiyyah lil-Istiqrāʾ, mentions this classification of certainty but ultimately offers a different division, distinguishing certainty into objective certainty and subjective certainty.

Primary Propositions (Awwaliyyāt)

According to the well-known and widely accepted definition, primary propositions (awwaliyyāt) are self-evident propositions for which the mere conception of the subject and predicate is sufficient for the issuance of judgment and assent. That is, in order to establish the predication of the predicate to the subject, no inference is required.

In some formulations of this definition, the relation between subject and predicate has also been added. However, this addition does not essentially differ from the well-known definition. For even in the common definition, alongside the conception of subject and predicate, attention to their relation is also implicit. Ultimately, what is relied upon in defining primary propositions is the absence of any need for inference.

Ṣadr al-Mutaʾallihīn defines awwaliyyāt in al-Asfār as follows: primary propositions are those propositions that do not require a middle term, nor sense perception, experience, testimony, or repetition for their affirmation¹⁸.

This definition, too, is very close to the well-known definition, though it is more precise in one respect: since neither an external cause nor an internal cause is required to establish the predicate for the subject, the reason for the self-evidence of primary propositions is not external. Rather, it is the essence of the subject itself that suffices for the affirmation of the predicate. In primary propositions, the mere conception of the subject is sufficient for the acceptance of the predicate.

Thus, according to the common definition, the absence of a middle term for affirming the predicate of the subject is sufficient.

Ibn Sīnā defines primary propositions in this manner: primary propositions are those propositions which the intellect itself affirms without the mediation of anything external. That is, the intellect perceives the truth of these propositions immediately, because the intellect, by its very nature, apprehends reality. Therefore, judgment and assent in such propositions are necessarily realized. In this class of propositions, believing and assenting depend on nothing beyond the manner in which the subject and predicate are conceived.

Some primary propositions are such that they are evident for all rational beings at once, while others are initially hidden and require attentiveness, precision, and reflection to become manifest. This need for attentiveness does not undermine their self-evident status, because the need arises from obscurity in the conception of the subject and predicate, not from any deficiency in the proposition itself. When the conceptions are clarified, assent follows immediately.

Ibn Sīnā, at the end of this discussion, points out that primary propositions may differ in clarity. Some are completely clear and immediately grasped, while others – although still primary – require interpretation and clarification due to ambiguity or subtlety in the concepts involved (subject or predicate). Since the criterion of primary propositions is the correctness of conception of subject and predicate, in cases where these conceptions are unclear, one must not hasten to deny the proposition. Rather, once the concepts are properly understood, assent will follow without any harm to the primariness of the proposition.

Ṣadr al-Mutaʾallihīn states: the acquisition of primary conceptual and propositional axioms through definition and demonstration is impossible, because the very conception of the impossibility of the conjunction of contradictories and the elimination of contradiction in demonstration—as well as all other self-evident judgments and propositions—rests upon those axioms themselves. Likewise, the relation of these axioms to the necessity of existence is such that, in the process of verification, they are indispensable. All propositions other than these are among the first intelligibles that are subject to investigation. Whoever denies the axioms is comparable to a sick person, and such a person cannot be cured through argumentation¹⁹.

Thus, the first argument against the denier of primary axioms is that his denial, in reality, affirms what he denies. That is, when someone claims, “I do not accept self-evident propositions,” he must nevertheless accept them, because one cannot both accept and reject something at the same time.

Note 1. As stated earlier, in primary axioms, the affirmation of the predicate for the subject occurs without inference, without syllogism, and without a middle term. Shaykh al-Raʾīs (Ibn Sīnā) also explicitly states that a sound intellect, untainted by sophistry and fallacies, will immediately assent to propositions once the concepts and the bounds of the propositions are correctly conceived²⁰.

However, some thinkers, by confusing conception with assent, have fallen into error regarding the denial of the principle of the impossibility of contradiction, or have erred in grasping the concept of contradiction itself. This is because one of the conditions of contradiction is unity of time, place, and respect. Therefore, denial of this principle is not truly possible; rather, it arises from conceptual ambiguity or verbal equivocation.

Just as some have imagined that denying the principle of the impossibility of contradiction follows from affirming divine omnipotence, on the grounds that God’s power extends even to impossible things, this too is a fallacy. Divine power pertains to possible things, not to impossibilities, and this confusion has been introduced in an attempt to generate a sophistical objection against self-evident principles.

Note 2. When the discussion turns to primary axioms, clarity and explicitness are assumed, and ambiguity has no place. Although self-evident propositions are free from error with respect to their truth and correspondence with reality, individuals may err in their subsidiary judgments concerning them. For example, one might mistakenly think that a certain proposition entails the conjunction of contradictories, whereas in fact it does not. In such cases, the error lies in the subsidiary judgment, not in the axiom itself.

As is the case with some proponents of pluralism, who accept the principle of the impossibility of contradiction in religion in principle, but deny it in its applications. This disagreement and error do not indicate any defect in the acceptance of axioms themselves, since they all share agreement on the general principles. Disagreement arises only in deriving particulars from principles, or in applying principles to specific cases.

Thus, the possibility of error in identifying instances or in understanding the limits of axioms does not undermine the axioms themselves. Even if there is ambiguity in the conception of a subject or predicate, this does not constitute a challenge to self-evidence; once the concepts are properly clarified, assent necessarily follows.

Note 3. Although primary axioms are self-evident, they themselves admit of degrees; thus, some are more primary than others. This gradation does not undermine their self-evident status. Rather, the difference lies in the clarity with which their subject and predicate are conceived. For example, both the impossibility of contradiction and the impossibility of the conjunction of contradictories are primary self-evident propositions; however, the latter is apprehended more quickly and more readily. For this reason, some thinkers regard the impossibility of the conjunction of contradictories as the most primary of all axioms. Nevertheless, this issue is conceptual rather than logical and does not compromise the primariness of either proposition.

Note 4. Primary propositions are not necessarily identical with analytic propositions. An analytic proposition is one in which the predicate is contained within the concept of the subject, such that the predicate is extracted from the subject itself—such as the proposition “Every human being is an animal.” Some primary propositions, however, are not analytic in this sense. In these propositions, although the subject and predicate must be conceived for assent to occur, the predicate is not conceptually contained within the subject.

Therefore, unless one accepts, as some philosophers such as Ustād Miṣbāḥ have argued, that the return of the impossibility of contradiction and the impossibility of the conjunction of contradictories to analytic propositions is justified, primary propositions cannot simply be equated with analytic judgments. On this view, primary propositions would be neither purely analytic nor purely synthetic, and in this respect they would not be reducible to analytic propositions.

Instances of Primary Propositions

The foregoing discussion from Ṣadr al-Mutaʾallihīn shows that he restricts primary propositions to the cases of the impossibility of the conjunction of contradictories and the impossibility of the coexistence of affirmation and negation.

Logicians, in their works, have mentioned various instances for primary propositions, including the following:

A thing cannot both be affirmed and negated at the same time (the impossibility of the conjunction of contradictories).
The necessity of a thing for itself, and the impossibility of a thing’s negation of itself.
Every contingent being requires a cause that brings it into existence.
The whole is greater than the part.
Things that are equal to one and the same thing are equal to one another.
Every even number is divisible into two equal parts.
Two contraries cannot coexist in the same subject at the same time (the impossibility of the conjunction of opposites).
One body cannot occupy two places at the same time.
Two bodies cannot occupy the same place at the same time.

ʿAllāmah Ṭabāṭabāʾī, after defining awwaliyyāt in Nihāyat al-Ḥikmah, writes that primary propositions include the following:

The whole is greater than the part.
A thing remains identical with itself.
A number is either even or odd.
The conjunction of contradictories is impossible.
The disjunction of contradictories is impossible.

He holds that these five are instances of primary propositions. However, with respect to the final two cases—(4) and (5)—he adds an important clarification: in each of these five propositions, the mere conception of subject and predicate is sufficient for assent, and no middle term is required. Yet, in the final two cases, although the assent is not self-evident, the conception is self-evident. Hence, they are considered the most primary of primary propositions (awwal al-awwaliyyāt).

Quṭb Rāzī, in his marginal commentary, points out that primary propositions are not all equal in clarity and obviousness. This is because their conceptions may differ in clarity for the mind, and may not be equally evident for all people at all times²¹. In other words, primary propositions differ with respect to the clarity of their conceptions, not with respect to assent.

Ustād Jawādī Āmulī, as well as the author of Sharḥ al-Manṭiq al-Jadīd, maintain that the domain of awwaliyyāt is restricted solely to the proposition of the impossibility of the conjunction of contradictories. Other propositions, although they may be self-evident, ultimately rely upon this principle. Even the impossibility of the disjunction of contradictories is grounded in this same principle.

Ustād Jawādī Āmulī’s argument is as follows: if the affirmation of A necessarily entails the negation of non-A, and the negation of non-A necessarily entails the affirmation of A, then this inference itself rests upon the impossibility of the conjunction of contradictories. In other words, the inference presupposes that A cannot both exist and not exist simultaneously.

Therefore, since we accept the impossibility of the conjunction of contradictories, we can also affirm the impossibility of the disjunction of contradictories. For this reason, other propositions—such as causal propositions and mathematical propositions—are not primary in the strict sense. They admit of syllogistic reasoning and demonstrative proof, and their ultimate foundation is the impossibility of the conjunction of contradictories (and, by extension, the impossibility of the disjunction of contradictories).

From the author’s point of view, with respect to the instances of primary self-evident propositions, the position of Ṣadr al-Mutaʾallihīn is correct, and awwaliyyāt possess only two genuine instances: the impossibility of the conjunction of contradictories and the impossibility of the disjunction of contradictories.

For example, according to Ustād Jawādī Āmulī, the proposition “the existence of A entails the negation of non-A” and the proposition “the negation of non-A entails the existence of A” are correct. However, this proposition itself presupposes the impossibility of the conjunction of contradictories. Likewise, the impossibility of the disjunction of contradictories is also grounded in the impossibility of the conjunction of contradictories. Thus, an individual who does not accept the impossibility of the disjunction of contradictories cannot consistently accept this claim either.

For this reason, both the impossibility of the conjunction of contradictories and the impossibility of the disjunction of contradictories occupy the same rank among the primary propositions, and all other propositions mentioned earlier are dependent upon these two.

Nevertheless, this disagreement concerning the instances of primary propositions has no epistemological consequence, because foundational propositions are, in any case, among the innate and primary axioms. This discussion, therefore, poses no challenge to the theory of foundationalism.

The Epistemic Status of the Principle of the Impossibility of Contradiction

Ustād Muẓaffar, in his works on logic and philosophy, maintains that the principle of the impossibility of contradiction (imtināʿ al-tanāquḍ) – such as the impossibility that one body occupy two places at the same time, or that two bodies occupy a single place – is among the primary self-evident propositions. By clarifying this point, he regards the principle of the impossibility of contradiction as the most fundamental of primary principles (awwal al-awwaliyyāt). He then raises objections and responds to them, formulating the issue in the following way:

What does it mean to say that the principle of the impossibility of contradiction is awwal al-awwaliyyāt? If other self-evident propositions are also primary, and if the mind issues judgment upon them merely through the presentation of subject and predicate, without any need for anything else, then what additional meaning does awwal al-awwaliyyāt have? And if the mind’s judgment in those cases depends upon the principle of the impossibility of contradiction, then those judgments are not truly self-evident but theoretical. In response to this difficulty, several positions are presented.

(a) Other propositions are not truly self-evident but are instead theoretical, and the claim that they are derived from the principle of the impossibility of contradiction is unacceptable. This view, however, is rejected, because it contradicts what is self-evident to every rational person. If all self-evident propositions were theoretical, then every inference would require premises; and as is well known, every inference requires at least two premises (a major and a minor). Thus, in addition to the principle of the impossibility of contradiction, we would need at least one more self-evident principle to constitute the first syllogism. Moreover, we would also have to accept another self-evident principle, namely that a conclusion follows from premises (the principle of inference in the first figure). Therefore, restricting self-evident principles exclusively to the impossibility of contradiction is not acceptable.

(b) Other self-evident principles are not independent axioms; rather, they are applications and specifications of the principle of the impossibility of contradiction in different domains. For example, in quantitative matters it appears as the law of equality; in causal matters it appears as the principle of the impossibility of effect without cause; and in other domains it takes other forms.

This theory is also unacceptable, because differences among propositions arise from differences in their constituent elements—that is, subject and predicate. The subject and predicate in this proposition are not the same as the subject and predicate in other principles.

(c) The principle of the impossibility of contradiction and other self-evident principles are all primary and fundamental, and all of them ultimately rest upon the impossibility of contradiction. The subtlety here is that the manner in which theoretical propositions depend upon self-evident propositions is different from the manner in which self-evident propositions depend upon the impossibility of contradiction. The dependence of theoretical propositions on self-evident propositions is like the dependence of a child on its parents—derivative and mediated—whereas the dependence of self-evident propositions upon the impossibility of contradiction is of a different kind and may be explained in two distinct ways:

1. Particular judgments consist in the absence of an impediment arising from the opposite side. For example, in the particular judgment concerning the proposition “Zayd is standing,” once the ruling that “Zayd is standing” is established, the possibility that “Zayd is not standing” is removed. This possibility, however, is not eliminated through the principle of non-contradiction alone; rather, certainty is achieved only through the principle of the negation of contradiction. If this principle were removed from human thought, the mind would never attain certainty regarding any particular judgment. Therefore, the dependence of all theoretical and demonstrative sciences upon the principle of non-contradiction is evident, since any judgment must possess definiteness and determinacy.

2. In the absence of the principle of non-contradiction in thought, no science would be able to prevent the existence of other sciences. Some sciences (particular cognitions) do not prevent the existence of other sciences. For example, the science that “this paper is white” does not conflict with the science that “this paper is standing upright.” However, certain sciences do prevent others by excluding a range of possibilities. For example, the science that “Zayd is standing” prevents the possibility that “Zayd is not standing.” This exclusion occurs only through the intervention of the principle of non-contradiction. Thus, if the principle of non-contradiction were removed from human thought, no science would be capable of excluding any other science. Consequently, nothing would prevent a person from simultaneously holding that “Zayd is standing” and “Zayd is not standing,” except the principle of non-contradiction.

If this principle were removed, human thought would collapse into absolute skepticism. No particular certainty would be attainable, even if hundreds or thousands of arguments accompanied it. Hence, according to this second interpretation, no particular certainty would remain, and the mind would wander endlessly between affirmation and negation without settling upon either. As a result, all scientific laws would be undermined, because a scientific law requires determinacy—namely, the selection and fixation of one side. If the intellect were inherently inclined in two directions (i.e., doubt), the concept of a scientific law would be meaningless.

From this perspective, all theoretical and self-evident propositions ultimately terminate in the principle of non-contradiction. However, it is more accurate to say that the validity of theoretical propositions rests upon this principle. The foundation of theoretical propositions relies upon it insofar as it serves as one of the premises of syllogistic reasoning. By contrast, in the establishment of other self-evident propositions, the principle of non-contradiction plays a role in repelling opposing possibilities and securing certainty. That is, to achieve certainty in a self-evident proposition, the principle of non-contradiction is required to eliminate the possibility of its negation.

A further distinction between grounding self-evident propositions in the principle of non-contradiction and grounding theoretical propositions upon it lies in the following: when a theoretical proposition is inferred through syllogistic reasoning, its dependence on the principle of non-contradiction is clearly visible as part of the inferential structure. However, in self-evident propositions, although reliance upon the principle of non-contradiction is real, it is not manifested in the form of a discursive inference.

Thus, the objections raised by Muṭahharī regarding this matter may be summarized as follows:

If all propositions were theoretically derived, none would qualify as primary self-evident truths, whereas some propositions are clearly accepted as self-evident.
Every syllogism requires two premises; however, not all propositions are capable of being assumed as premises.
If one were to deny the principle of non-contradiction, the denial itself would presuppose its truth, since contradiction would then become possible.

In response, it must be said that the denial of the principle of non-contradiction does not involve denying it as a proposition, but rather undermining its function. In such a case, contradiction itself becomes permissible, and the circularity objection dissolves. Nonetheless, this move leads inevitably to the collapse of certainty and knowledge altogether.

ʿAllāmah Ṭabāṭabāʾī, concerning the difference between grounding theories and self-evident propositions in the principle of non-contradiction, writes:

“The difference between self-evident propositions and theoretical propositions is that theories depend upon others for the reception of matter and form, whereas self-evident propositions possess their own matter and form. For in nature, whenever a composition is posited, its ultimate matter is analytic, and no further matter remains beyond it—rather, it is itself the matter. Therefore, every proposition ultimately requires the proposition of the impossibility of the conjunction and elevation of contradictories (in philosophical terminology), except for the kind of requirement that theories have for self-evident truths, which is a material and formal requirement.”

From this statement it is concluded that, since the materials of the propositions that serve as premises (muqaddimāt) influence the outcome of the conclusion, the composition and structure of the premises likewise affect the result. Thus, when the materials of propositions—that is, their content—are self-evident, both their matter and form are self-evident, and the conclusion too will be self-evident. In this sense, when a theoretical proposition returns to self-evidence, it either arises from matter itself or from form itself, and there is no internal dependence upon another judgment.

What has been stated—that all propositions depend upon the proposition of the impossibility of the conjunction and elevation of contradictories—refers to the scientific and judgmental dependence, not to material or formal dependence.

Accordingly, in Nihāyat al-Ḥikmah, he writes:

“The first of the first principles is the principle of the impossibility of the conjunction of contradictories and the impossibility of their elevation. About these two it is said: affirmation affirms affirmation, negation negates negation, affirmation negates negation, and negation affirms affirmation. This is a self-evident truth, whose knowledge does not depend on any theoretical proposition, nor even on other self-evident propositions, such as ‘the whole is greater than the part,’ and the like. Rather, it is the first proposition to which assent is given, and upon which all theoretical and self-evident sciences rely in demonstrative syllogisms. If doubt were admitted into it, all propositions would become doubtful and knowledge would collapse from its foundation.”²²

The statement of ʿAllāmah Ṭabāṭabāʾī differs from that of Ustād Muṭahharī. In explaining the dependence of primary self-evident truths upon the principle of non-contradiction, Muṭahharī emphasizes the dependence of theories upon self-evidents, and interprets the dependence of the first principles upon the first of the first principles in two ways. By contrast, ʿAllāmah Ṭabāṭabāʾī explicitly holds that all propositions—both theoretical and self-evident—ultimately depend upon the propositions of the impossibility of conjunction and elevation of contradictories, while distinguishing between scientific dependence and material–formal dependence.

In simpler terms, two types of certainty are distinguished:

Certainty in affirming a predicate for a subject, and
Certainty in negating a predicate from a subject.

The totality of these certainties ultimately takes shape through the principle of non-contradiction, which prevents the simultaneous affirmation and negation of the same predicate with respect to the same subject. However, the need of theories for this principle is due to the fact that they aim to establish necessity and certainty for predications, whereas self-evident propositions, in their own right, do not require proof but still rely on the principle of non-contradiction to exclude opposing possibilities.

According to this view, the scientific and judgmental stability of all propositions—whether theoretical or self-evident—is secured through this principle. Sensory perceptions, observations, and experiences do not require syllogistic proof, yet the possibility of opposing judgments concerning them is eliminated by the same principle. For example, when it is said that “the weather is now cold,” the certainty of this judgment does not rest upon the principle of non-contradiction in its affirmative content; rather, the sensory judgment itself arises directly from perception. Nevertheless, the exclusion of the opposite judgment—namely, that “the weather is not cold”—is secured through the principle of non-contradiction.

Thus, sensation is not subject to error insofar as it is sensation; error occurs only when the mind intervenes and issues a judgment beyond mere perception. The mind sometimes misinterprets or distorts its own sensory data, but this does not undermine the foundational role of the principle of non-contradiction in securing judgmental certainty.

For example, sense perception sees a star as small, while the intellect simultaneously perceives it as large. The intellect observes both its smallness and its largeness, and then—by making use of prior information and intervening in that perception—issues another judgment about the star. In every case, sensory perception and mental judgment are distinct. What is obtained from the sensory side is a perceptual cognition, whereas the judgment that arises from the rational side is acquired through the exclusion of the opposite, using the principle of non-contradiction.

For instance, when we say “the air is warm” (that is, warmth exists in the air), the coexistence of the absence of warmth with the presence of warmth is impossible; because the conjunction of contradictories is impossible. Thus, by excluding the absence of warmth, the existence of warmth is established as necessary.

Ibn Sīnā notes in his Ishārāt:

“As for propositions whose middle terms are absent, they are propositions whose assent occurs due to the exclusion of the middle; yet this does not mean that the middle is entirely absent from the intellect. Rather, the intellect reaches certainty by eliminating the middle, just as in propositions such as ‘two is not half of four’.”²³

Shahīd Muṭahharī has explained this view while clarifying the statements of ʿAllāmah Ṭabāṭabāʾī. However, it appears that ʿAllāmah Ṭabāṭabāʾī had something further in mind. In any case, several points emerge here:

1. All propositions—whether self-evident or theoretical—require the principle of non-contradiction for the acquisition of reinforced certainty. This does not mean that only self-evident propositions require this principle for inference and for negating the opposite; rather, in all theoretical propositions as well, such as the proposition “the world is originated,” which is composed of two premises—“the world is changeable” and “every changeable thing is originated”—the conclusion that “the world is originated” would not follow unless the principle of non-contradiction were operative. Thus, in general, all propositions require the principle of non-contradiction for the acquisition of reinforced certainty.

2. The principle of non-contradiction does not merely generate reinforced certainty for primary self-evident truths (fitriyyāt), but also plays a role in generating primary certainty. In other words, the relationship between the principle of non-contradiction and the fitriyyāt is a generative relationship. What appears in reality as the argument from circularity (istidlāl al-dawr) is in fact grounded in the principle of non-contradiction, and even the certainty of theoretical propositions with respect to the affirmation of a predicate for a subject is realized through this principle.

In response to this point, Shahīd Muṭahharī says: if we claim that the relation between these propositions and the first of the first principles is generative, then it would be necessary to posit more than one self-evident principle. However, it must be said that this is not required, because the syllogism formed here is not an ordinary syllogism but an exceptional syllogism. In an exceptional syllogism, the assumption of the negation of the proposition is posited, and the contradiction that follows is sufficient for establishing the conclusion through the principle of non-contradiction. For example, if the conjunction of contradictories were possible, it would follow that “a false statement is true” (as in the famous example “everything is false”). In reality, this is a hidden premise that appears in the form of a contrary syllogism.

If an incremental syllogism were actually formed, then more than one self-evident principle would indeed be required. Accordingly, as Ustād Jawādī Āmulī states, the argument from circularity and the principle that “the whole is greater than the part” and all the first principles are generative in relation to one another.

However, Shahīd Muṭahharī adds that even if this relationship were generative, this would amount to a circular or mutually generative relationship. In response, it must be said that although these propositions are theoretical insofar as they are derived through inference, they are not primary self-evident truths; rather, their self-evidence is secondary. Thus, the relationship between theories and the principle of non-contradiction is a generative relationship, and this relationship may be realized either through an exceptional syllogism or through an incremental syllogism. Provided that, in all such cases, theoretical propositions are grounded upon the principle that negates the opposite and establishes reinforced certainty.

The fact that these propositions possess inference and syllogistic structure does not undermine their status as self-evident in a secondary sense.

Therefore, the meaning of being “first of the first principles” with respect to a proposition—given that the principle of the elevation of contradictories is also self-evident—is that in the first of the first principles, the conception of the subject and predicate is simpler than in the principle of the elevation of contradictories.

The Selected Theory

In the discussion on grounding the sciences in self-evident truths, the following conclusions may be stated overall:

All propositions required for the establishment of knowledge and certainty are ultimately grounded in the principle of the impossibility of contradiction. Through this principle, the possibility of the opposite is invalidated and certainty is achieved. However, this grounding is generally realized through exceptional syllogisms.
Some propositions stand in a generative relationship with the principle of non-contradiction; that is, the principle itself gives rise to them. For example, the argument from circularity (dawr), which arises from the precedence of a thing over itself, is itself derived from the principle of non-contradiction.
Other propositions ultimately terminate in perceptibles (maḥsūsāt), analytic propositions, intuitive judgments (wijdāniyyāt), or primary self-evidents (awwaliyyāt). Concomitants (mutawātirāt) and experiences (tajribiyyāt) reduce to perceptible propositions, while intuitions reduce to analytic propositions or primary self-evidents.

Perceptibles and Observations

Perceptibles and observations constitute the second set of instances of self-evidents (or certainties). Perceptibles are propositions obtained through the senses. Sensory data acquired through the external senses are called sensations (ḥissiyyāt)—such as knowledge of heat, coldness, light, etc.—while data acquired through the internal senses are called intuitions (wijdāniyyāt)—such as knowledge of fear, grief, love, hunger, and the like.

Thus, perceptibles and observations as a whole are divided into two categories: sensations and intuitions. In both cases, assent to them occurs through sensory cognition, whether external or internal.

Note 1: Sensations and intuitions—alternatively described as information obtained through external senses and internal senses—fall within the scope of acquired sciences. When we speak of sensations or of information obtained through the external senses, what we mean is not the mere presence of a sensible form in the mind, which would constitute immediate knowledge (ʿilm ḥuḍūrī). Rather, what is meant is the direction or mode of representing that form from the external world. In contrast, when we speak of intuitions or of information obtained through internal senses, we are not referring to immediate knowledge itself—such as grief, joy, fear, or hunger—but rather to conceptual knowledge of these states. That is, while we possess immediate knowledge of joy, grief, hunger, thirst, etc., the mind abstracts, conceptualizes, and represents these states. Hence, from the perspective of representation, these cognitions are acquired, whereas from the perspective of presence, they are immediate.

Note 2: As stated, what is meant by perceptibles are propositions whose assent is effected through sensory cognition. In this context, sensory cognition is prior to the formation of propositions. For example, fire is first perceived by the senses, and only afterward does one assent to propositions such as “fire is hot,” “fire is luminous,” and so forth. The question arises: is this sensory assent itself an operation of the senses, or is it an operation of the intellect?

Most philosophers hold that assent is an act of the intellect, and judgment is issued by the intellect. Ibn Sīnā states: “As for perceptibles, they are propositions whose assent is acquired from sense.”²⁴

This expression indicates that while sense assists the intellect in assenting to perceptible propositions, the act of assent itself belongs to the intellect. In other words, sense perceives fire and heat as individual forms, but the intellect grasps the relation between them and affirms the judgment.

The mind does not grasp the companionship of fire and heat merely by sensation, because companionship is an abstract, relational concept and thus an intelligible of the second order. The apprehension of such intelligibles is an operation of the intellect. Therefore, sense is never subject to error or correctness, since error and correctness pertain to judgment, which is an intellectual act. Sense merely perceives particulars, whereas judgment and assent fall within the domain of the intellect.

Ibn Sīnā says: “Sense is the path to knowledge, not the agent of knowledge.”²⁵

This statement clearly affirms that scientific knowledge and assent are acts of the intellect, while sense functions solely as an instrument and a means.

Note 6: In general epistemology—among both Muslims and non-Muslims—there are three main theoretical positions concerning sensory reports (sense data):

Direct Realism:
This view holds that in sensory reports, reality itself is directly perceived. Only the sensible object is known as it truly exists. Thus, when we say “I see this book,” what is meant is not that “there is an image of this book in the mind,” but rather that the very external object enters cognition directly and possesses reality. This position denies that what is perceived is merely a mental representation detached from reality. Sensory knowledge, on this account, corresponds directly to external reality.
Indirect (Representative) Realism:
According to this view, what is immediately perceived in sensation is not the external object itself, but a mental form or representation produced by the external object. The external object exists independently, but knowledge of it occurs through a mediating mental image. Thus, sensation involves both an external cause and an internal representation, and cognition is indirect.
Phenomenalism / Subjectivism:
This position argues that what we know through sensation are only appearances or phenomena, not external realities as they are in themselves. Sensory data are confined to subjective experiences, and claims about external reality go beyond what sensation alone can justify.

The first position—direct realism—maintains that sensory reports refer directly to reality itself and that the sensible object, as perceived, is real. Hence, statements such as “I see this book” are taken to mean that the book itself is directly present to cognition. This view rejects the idea that sensory knowledge is merely of internal images detached from reality.

However, this theory is not accepted by idealists and sophists. They argue that what is perceived cannot be equated straightforwardly with external reality, and that sensation alone does not guarantee the existence of an independent external object corresponding exactly to what is perceived.

In contrast, proponents of indirect realism accept that sensation provides knowledge, but only through the mediation of mental representations. Thus, while the external object exists, the immediate object of knowledge is the mental form produced in the knower.

Finally, phenomenalist approaches restrict certainty to subjective sensory experiences themselves and deny that sensation yields knowledge of external reality as such.

These differing theories illustrate the broader epistemological debate about the status of sense perception, the relationship between mind and world, and the extent to which sensory knowledge can ground objective certainty.

Indirect realism holds that the model of sensory reports is both a report of observation and a report of reality. That is, something other than the sensed object is real. Sensory objects per accidens also possess descriptive reality.

In the act of observing a book, there are two reports: one is “I see a book,” and the other is “the book exists externally.” The first report is immediate, presentational knowledge and is self-evident; the second is an acquired scientific report which, as discussed earlier, is demonstrable through argument and proof. This theory is acceptable to Islamic philosophers.

Phenomenalism, derived from Kant’s framework, is the belief that external objects and mental objects must be distinguished (this distinction between external existence and mental existence is discussed in Islamic philosophy). According to this view, what appears in the mind is stable and enduring, while the noumenon—the thing in itself—is external. Objects are never known in themselves; there is always a difference between the object as it is in itself and the object as it appears to us (i.e., external versus mental).

This ontological distinction is not identical with the claim that existence is divided into mental and external existence; rather, it is another form of ontological differentiation. However, this distinction is rejected. When we speak of appearance and noumenon, the noumenon is not something external in the sense of an independent reality; rather, it is merely the limit of appearance, and nothing external corresponds to it. Thus, in this theory, although mental reality is affirmed, external reality is denied, and everything is reduced to appearance. There is no reality beyond appearance (similar to Shaykh’s position). This view has been adopted by later thinkers influenced by Kant, such as Heidegger, Husserl, Gadamer, and others.

The theory we accept is the second theory—namely, indirect realism—which is the view of Islamic philosophers. According to this view, sensible objects per accidens have reality, and sensory reports initially concern essential sensibles; subsequently, through them, accidental sensibles are apprehended, and mental forms refer beyond themselves.

In clearer terms: although Kant attempted to affirm reality by accepting external reality, merely accepting external reality is insufficient. One must also accept the correspondence between mental forms and external reality. If correspondence is denied, then external reality itself becomes questionable, because at minimum, this report—“there is something external”—requires correspondence to be true. If correspondence is denied, that report too collapses.

An important point is that some perceptual data have no external referent, and their origin cannot be external—for example, modern physics shows that colors as qualities do not exist externally as they are perceived. They are not found outside; rather, what exists externally are electromagnetic waves and physical structures. Therefore, from every perceptual datum one cannot infer an externally sensible object per accidens.

Fitriyyāt (Innate / Natural Propositions)

Fitriyyāt have various technical definitions, but they function as a shared verbal category. Here, they refer to propositions whose syllogisms accompany them—that is, their middle terms are inherently present. These are propositions whose proofs are immediately available to the mind; although one may not consciously attend to them, they do not require deliberate reflection or mental effort. As soon as the components of the proposition are conceived, the middle term presents itself automatically.

For example, the affirmation that four is an even number occurs because, together with the conception of the number four, the mental syllogism is immediately formed as follows: four is divisible into two equal numbers; whatever is divisible into two equal numbers is even; therefore, four is even.

Jawādī Āmulī writes regarding fitriyyāt that the clarity and immediacy of some of these propositions has led many fitrī propositions to be counted among the awwaliyyāt (first principles). However, although a fitrī proposition does not require a separate proof, it is not because it lacks a reason; rather, its reason is inseparable from it. Consequently, clarity alone does not make a proposition awwalī.

Among fitrī propositions are those traditionally listed as awwaliyyāt, such as: the impossibility of something being both necessary for itself and impossible for itself; the impossibility of a thing being both affirmed and negated of itself; and the principle that the whole is greater than the part. In these cases, the impossibility of contradiction follows necessarily, since affirming the opposite would require the coexistence of existence and non-existence, or of identity and non-identity.

The reason these propositions are fitrī is that negating them necessarily entails contradiction. For example, if one were to deny that the whole is greater than the part, one would have to accept that the whole is equal to or smaller than the part—both of which lead to contradiction. Similarly, if one were to deny that two times two equals four, one would implicitly deny the identity of numerical relations, which again entails contradiction.

Thus, fitrī propositions differ from purely awwalī propositions in that they involve a middle term, but that middle term is immediately present to the mind and does not require independent discovery. Their syllogisms are formed spontaneously and inseparably from their conception.

Because of this, fitrī propositions are not in need of external argumentation, yet they remain inferential in structure. Their certainty arises from the immediacy with which their middle terms appear, not from the absence of a syllogistic relation. Hence, fitriyyāt occupy an intermediate position between awwaliyyāt and theoretical propositions: they are inferential, but their inference is innate, immediate, and unavoidable.

In summary, fitrī propositions are those whose truth becomes evident as soon as their terms are conceived, because the middle term is naturally present in the mind. They do not require external proof, not due to a lack of reasoning, but because their reasoning is intrinsic to their very conception.

Sayyid Ali

Sayyid Ali studied in the seminary of Qom from 2012 to 2021, while also concurrently obtaining a M.A in Islamic Studies from the Islamic College of London in 2018. In the seminary he engaged in the study of legal theory, jurisprudence and philosophy, eventually attending the advanced kharij of Usul and Fiqh in 2018. He is currently completing his Masters of Education at the University of Toronto and is the head of a private faith-based school in Toronto, as well as an instructor at the Mizan Institute and Mufid Seminary.

Footnotes

Al-Ījī, al-Mawāqif, vol. 1, p. 90.
Al-Mawāqif, ibid., p. 92
Ibn Sīnā, al-Ishārāt, vol. 3, p. 213
Ṣadr al-Mutaʾallihīn, al-Asfār, vol. 3, p. 518
See: Sabzawārī; Ṭabāṭabāʾī, Nihāyat al-Ḥikmah, p. 252
Muẓaffar, Usūl al-Fiqh, vol. 1, pp. 232–233
Al-Asfār, vol. 3, p. 402
Fārābī, al-Qiyās, vol. 1, p. 148
al-Asfār, vol. 3, p. 423
Al-Fārābī, al-Qiyās, vol. 1, p. 19
Ibn Sīnā, al-Ishārāt, vol. 1, p. 129
al-Ījī, al-Mawāqif, vol. 2, pp. 36–38
Al-Taftāzānī, Sharḥ al-Maqāṣid, vol. 1, p. 250
Suhrawardī, Talwīḥāt, pp. 118–123
See: Ṭūsī; Mullā Ṣadrā; Ṭabāṭabāʾī
Ṣadr al-Mutaʾallihīn, al-Asfār, vol. 1, p. 445¹⁶.

This definition is essentially no different from the well-known one; rather, it further emphasizes the sufficiency of the conception of the two terms of the proposition. That is, the mere conception of subject and predicate, whether in affirmative or negative propositions, is sufficient for judgment and assent in primary propositions.

Ustād Jawādī Āmulī states: a primary proposition is one in which the affirmation of the predicate for the subject does not require any external cause nor any internal cause¹⁷Jawādī Āmulī, Raḥīq al-Makhtūm, vol. 3, p. 145
Ṣadr al-Mutaʾallihīn, al-Asfār, vol. 3, p. 443
Ibn Sīnā, al-Shifāʾ, Logic; see also: Ṭūsī; Bahmanyār; Sabzawārī; Ṭabāṭabāʾī; Miṣbāḥ Yazdī
Ibn Sīnā, al-Ishārāt, vol. 1, p. 51
(Ṭabāṭabāʾī, Nihāyat al-Ḥikmah, pp. 252–253
Ibn Sīnā, al-Ishārāt, vol. 1, p. 219
Ibn Sīnā, al-Shifāʾ, Logic, vol. 1, p. 21
Ibn Sīnā, al-Shifāʾ, Metaphysics, p. 148