In classical Greek philosophy 'dialectics' meant a specific method of discussion in which the debate between the representatives of opposite points of view begins from preliminaries admitted by both the sides and proceeds until one of the points of view is affirmed or a new conclusion is reached by the way of synthesis of formerly opposite viewpoints.
Dialectic in modem Western philosophy is not a method of discussion but a method of explaining reality and a general law of the universe according to which movement is a continuous development of oppositions and contradictions, their merging and reconciliation. The idea is an old one, foreshadowed by Empedocles (who explained change as a conflict between the world forces of Love and Strife) and Zoroaster, and embodied in the 'golden mean' of Aristotle, who held that "the knowledge of opposites is one." Hegel was the first to establish a complete logic (and metaphysics, which in Hegel is same as logic) on the basis of the notion of dialectic.
In this logic, which is claimed to govern thought and existence, the fundamental principle is one of thesis, antithesis, and synthesis, which involves a constant 'taking up' and reconciliation of pairs of contradictories in higher, more comprehensive and penetrating ideas, until finally all oppositions are overcome in the all-inclusive, all-reconciling and all-explaining Absolute Idea.
Hegel views conception as a hierarchy of syntheses whose skeleton is constructed of ascending triads in which seemingly antagonistic concepts are reconciled by dialectic in higher logical concepts. The most basic triad involving the concepts of being and non-being as thesis and antithesis yields the synthetic concept of becoming. The ideas of becoming and change involve the concepts of identity and difference which are reconciled in the concept of essence. The concepts of essence and existence, whole and part, appearance and reality are resolved in the concepts of ground and force. The concept of force suggests those of actuality and potentiality, whose dichotomy is reconciled in the concept of fact. Also the notion of fact suggests those of necessity and freedom, which are resolved in the concept of 'nature of things'
. Now we are confronted with the thesis and antithesis of substance and its attributes or accidents. This contradiction is overcome by regarding the substance as the cause of its attributes. Here cause contains the effect and so cause and effect become one. Similarly final and efficient causation are synthesized in the identity of means and end, which are neither external to nor distinct from each other, by the concept of process. The world-process and the Absolute are one; it is its own cause and its own goal. Hence the actual is the ideal; on the moral plane, value and fact are identical.
Hegel's stand on the law of contradiction is dubious. As can be seen, the driving motive behind every Hegelian synthesis is avoidance of contradiction; i.e. it is inspired by belief in the impossibility of contradiction. Moreover, he holds that the nature of Reality can be deduced from the sole consideration that it must not be self-contradictory.
On the contrary, according to Hegel, truth and falsehood are not sharply defined opposites, as is commonly supposed; nothing is wholly false and nothing that we can know is wholly true. The truth is the 'whole', and nothing partial is quite true. Whatever the value of his arbitrary analysis of concepts, it does not seem correct, on the whole, to hold that Hegel rejects the principle of contradiction.
Hegel is one of the most confused of philosophers. His philosophy is difficult because it is difficult to understand confusion. The Marxist interpretations, or misinterpretations, of Hegelian dialectics have added to this difficulty. Therefore, when al-Sadr criticizes Hegel, he has the Marxist interpretation of Hegel before him.
Thus when we see al-Sadr charging Hegel with the complete rejection of the principle of contradiction and with holding that contradiction is not only the primary principle of all knowledge but the general law of the universe, we should understand him as criticizing the Marxist interpretation of dialectics rather than Hegel. With these remarks now we turn to al-Sadr's criticism of Marxist dialectics.
According to the Marxists, the dialectical method is characterized by four main points: (1) The movement of development, (2) the contradiction of development, (3) the leaps of development, and (4) the general linkage. These are supposed to replace the four laws of thought recognized by formal logic: the law of identity, the law of contradiction, the law of conversion, and the law of demonstration. Al-Sadr then goes by one on to deal with the four points of the dialectical logic one.