Part One: the Theory of Knowledge (chapter I)
The first chapter in this section is devoted to the epistemological problem of the source of concepts and judgements. First the author examines the Platonic doctrine of Recollection, then the rationalist theory, and following that the empirical theory. The Platonic theory is false because soul does not exist in an abstract form prior to the existence of the body, being the result of substantial motion in matter. It is by means of this movement that it acquires an immaterial existence not characterized by material qualities and free from the laws of matter.
The rationalist theory that some concepts are innate or a priori is not refutable if interpreted to mean that innate ideas exist in the soul potentially, becoming actual as the soul develops.
The empirical theory, first propounded by John Locke, holds that there are no innate ideas; all our ideas without exception are derived from experience. It was adopted by Marxism. However, the empirical theory as admitted by Hume fails to explain how we form such concepts as that of causality; for that which is derived from the senses is succession, not causality. The rejection of the principle of causality by empiricists does not solve the difficulty, because the fact remains that we do conceive causality, which is not given in sense perception.
Al-Sadr then goes on to the Abstraction theory (nazariyyat al-'intiza') favoured by the Islamic philosophers in general. According to this theory, concepts are of two kinds: primary and secondary. The primary ones are products of sense-perception. The secondary ones are produced from the primary concepts by the mind through the means of 'abstraction.' The secondary concepts although derived from the primary ones transcend them and are the inventions of the mind.
Moving from concepts to judgements, al-Sadr selects here the rational and empirical theses about the source of judgements for discussion.
- According to the rationalists, knowledge (in the form of judgements or propositions) consists of two kinds. The first kind is primary, self-evident, and intuitive. It includes such propositions as the principle of contradiction, and such statements as 'The whole is greater than the part', 'One is half of two', 'A thing cannot have contradictory attributes at the same time', and so on. The other kind is what the author calls 'theoretical' knowledge, whose truth cannot be established except in the light of the first kind. Among the examples given are: 'The earth is spherical', 'Heat is caused by motion', 'Infinite regress is impossible', 'The angles of a triangle are equal to two right angles'.
The author does not seem to be right here in putting two different kinds of statements in one class called 'theoretical knowledge'. 'The earth is spherical' is not the same kind of judgement as 'The angles of a triangle are equal to two right angles'. The former requires observation and inference for its proof, while the latter can be established by pure reasoning. The same distinction applies to the two statements 'Heat is caused by motion' and 'Infinite regress is impossible'.
All knowledge is based on previous knowledge, which in turn depends on knowledge preceding it. The a priori or primary knowledge is that irreducible remainder which does not arise from any previous knowledge. A part of primary knowledge, consisting of such general principles as the law of contradiction, constitutes the basic condition of all knowledge. Without it no general proposition can be affirmed.
It is this knowledge independent of experience that makes metaphysics possible.
The progression of thought is from universal to more particular propositions. This is true even in the experimental sciences, which cannot dispense with the universal principles of causality and uniformity of nature. Experimentation also, without the application of necessary rational laws, does not lead to general scientific truths. The Islamic philosophers, including al-Sadr, espouse this theory.
- According to the empiricists sense experience is the primary source of all knowledge. They do not admit the existence of any necessary rational knowledge prior to experience. There can be no knowledge of universal truths prior to experience. Their position makes metaphysics and deduction impossible.
The empirical doctrine has to be rejected for the following four reasons.
First, either the empirical doctrine is prior to experience or it is not. If it is, it refutes itself. If it is derived from experience, the validity of experience as a criterion of knowledge has not yet been established. Second, empiricism fails to affirm the existence of matter and the external world, which cannot be affirmed except by primary rational knowledge. Thus the metaphysical realities are not the only ones which depend for their affirmation on the rational method.
Third, experience by itself is not sufficient to assert the impossibility of anything. All that experience can affirm is non presence or at the most non-existence. The notion of impossibility can be accepted only on rational grounds, not on the basis of experience. If the notion of impossibility is denied, anything, including contradiction, becomes possible. The possibility of contradiction leads to the collapse of all knowledge and science.
Fourth, the principle of causality cannot be demonstrated by the means of the empirical doctrine. All that experience can affirm is succession and contiguity, not causal necessity.
The author then turns to the effort of Hume to show how the 'feeling' of necessary connection implicit in the concept of causality arises from experience: the theory of association of ideas. According to Hume, the habit of leaping forward to and expecting the sequent associated with the antecedent becomes so ingrained by continual repetition of their conjunction as to make the mind feel that when the one event occurs the other simply must follow it. Events so habitually conjoined and associated as to be accompanied by this feeling of must are called cause and effect, and the relation of simple sequence is turned into one of causation. Al-Sadr offers five reasons for rejecting this explanation. First, if it were true, no scientist would be able to confirm a causal relation between two things in a single experiment, where there is no repetition of the conjoined events to produce the feeling of necessity. Similarly, many times, belief in a causal relationship is not strengthened by further repetition of events involving a cause and its effect.
Second, when we take the associated ideas of two events regarded as being in cause-effect relationship, is the relation between these two ideas that of mere conjunction or necessity? If it is mere conjunction, the element of necessity implied in their association is not explained.
Third, the necessity of the principle of causality is not a psychological necessity but an objective one.
Fourthly, the mind distinguishes between cause and effect even when they are completely conjoined (e.g. the movements of the pen and the hand while writing).
Fifthly, it often happens that two events are frequently associated without producing the belief that one of them is the cause of the other (e.g. day and night). Empiricism cannot provide the basis for the sciences, which are based on some rational principles that are not subject to experimentation, viz., the principle of causality, the principle of harmony between cause and effect, and the principle of non contradiction. The scientist, in framing his theories, passes from these general principles to particular hypothesis through a process of syllogistic reasoning.
Of course, experience has a high value, but it itself stands in need of a rational criterion. This criterion is primary rational knowledge.
The rational theory of knowledge also explains the quality of necessity and certainty that distinguishes the propositions of mathematics from the propositions of the natural sciences. This is because mathematics is entirely based on primary rational principles. Some empiricists have tried to explain this difference by stating that mathematical propositions are analytic (tautological). Yet even mathematical statements would not be certain had it not been for their reliance on certain rational principles, such as the law of contradiction. Moreover, all mathematical statements are not analytic, such as, ,The diameter is shorter than the circumference'.
How does primary knowledge emerge when it is not present at birth and in all men at all times? The answer is that the primary judgements proceed from the innermost being of the soul after it has formed the necessary conceptions, directly or indirectly, as a result of experience. As the soul develops through substantial movement, the primary knowledge, which exists in it potentially, becomes actual.