Thus the metaphysical realities are not the only ones which...

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.