The most interesting part of the Critique of Pure Reason is known as the antimonies. In these, Kant shows the contradictions that exist in thought. Thus, starting with the laws of formal logic, and applying them to the world of experience, Kant precedes to show the contradictions which arise. Kant takes this as proof of the unknownability of the Thing-in-Itself, instead of seeing that the contradictions are objective, and present in the phenomena themselves.
The fundamental problem here is: How do the forms of logic relate to the real world? The categories of formal logic tell us absolutely nothing about the real world. It was the task of science to discover the laws of the real world through observation and experiment. However, the picture of the world was never complete, since science would inevitably discover new fields all the time, and would have to constantly readjust its theories and propositions. This is the real process. However, Kant drew entirely different conclusions.
Not until Hegel was the reason for these contradictions explained. The problem arises from the nature of formal logic itself, which takes opposites to be mutually exclusive. For example, the logical category of identity presupposes its opposite—difference. When we say that something is, we think we have identified it. However, it only has identity in comparison to other things. John is John, because he is not Peter, Paul, etc. Thus, identity presupposes difference, and has no meaning in isolation. In general, things have no meaning unless taken together with their opposites. Life cannot be understood without death. North and South, right and left, male and female, good and bad, can only have meaning in relation to their opposites. The unity of opposites is a fundamental fact of existence.
Hegel later explained that pure, undifferentiated being is the same as nothing. If we merely confine ourselves to the assertion that a thing is, without explaining its concrete properties, internal contradictions, motion and change, and manifold relations, we do not really grasp the truth about it. Without further concretisation, simple being turns out to be an empty abstraction. This particular contradiction ("antimony") can only be resolved by understanding that being and not being are not mutually exclusive, but are combined in the process of becoming.
Similarly, the polar opposites cause and effect have to be united as interaction. If we attempt to isolate a particular cause and effect, immediately land ourselves in a contradiction, since there are always an infinite number of causes which precede the given case; in fact, behind each isolated fact is the whole history of the universe. Similarly, if we attempt to understand a particular fact as a cause, we will enter into an endless chain of phenomena, following it in time, into infinity.
How to solve this contradiction? If we keep within the rules of formal logic, the only solution to Kant’s antimonies, is to deny the validity of exactly one half of its categories, recognising only the other half. The mediaeval Schoolmen, for example, declared that chance (accident) to be a purely subjective concept, a product of ignorance of the causes. Everything in the universe was absolutely determined, in fact, preordained from the beginning to the end by the Supreme Being. Likewise, Identity was proclaimed to be absolute, and Contradiction rigorously prohibited by the traditional logic.
Kant points out in the section on the antimonies that contradiction is not just a trick of sophists, but is inevitable. The antimonies, where he gives two sets of proofs for two contrary propositions, are "not mere sophistries—are not fallacious, but grounded on the nature of reason..." (Ibid, p. 304). For example, in cosmology, which he was deeply interested in, such questions as whether the universe has a beginning or not.
"Unfortunately for speculation—but perhaps fortunately for the practical interests of humanity—reason, in the midst of her highest anticipations, finds herself hemmed in by a press of opposite and contradictory conclusions, from which neither her honour nor her safety will permit her to draw back. Nor can she regard these conflicting trains of reasoning with indifference as mere passages at arms, still less can she command peace; for in the subject of the conflict she has a deep interest. There is no other course left open to her, than to reflect with herself upon the origin of this disunion in reason—whether it may not arise from a mere misunderstanding. After such an inquiry, arrogant claims would have to be given up on both sides; but the sovereignty of reason over understanding and sense would be based upon a sure foundation." (Ibid, p. 282.)
The real resolution is the never-ending process of deepening knowledge:
"For it (reason) can give no answer to our question respecting the conditions of its synthesis—except such as must be supplemented by another question, and so on to infinity. According to it, we must rise from a given beginning to one still higher; every part conducts us to a still smaller one; every event is preceded by another event which is its cause; and the conditions of existence rest always upon other and still higher conditions, and find neither end nor basis in some self-subsistent thing as the primal being." (Ibid, p. 284.)
Every answer only gives rise to a new question, and so on ad infinitum. There are no final answers. No end to the process. Therefore, dialectical thought is undogmatic and open-ended. The solution to the supposedly "unsolvable" problems is given by the never-ending process of the history of science and human thought in general. The only way of resolving the contradictions in thought was by a complete overhaul of logic, breaking down the old rigid schemas, which did not and could not faithfully reflect the reality of a moving, changing, living, contradictory world. Hegel hailed Kant for reintroducing the notion of contradiction into logic.
"And to offer the idea that the contradiction introduced into the world of Reason by the categories of Understanding is inevitable and essential was one of the most important steps in the progress of Modern Philosophy." (Hegel, Logic, p. 77). However, having posed the question, Kant was unable or unwilling to provide the answer. "But the more important the issue thus raised, the more trivial was the solution." (ibid).
Kant did not achieve this revolution. But his great merit was to point the way forward. Kant gave philosophy a new lease of life, by subjecting the old forms of thought to a thorough criticism, revealing their inherently unsatisfactory and contradictory nature The Critique of Pure Reason showed that contradictions were inherent in thinking. In so doing, Kant reintroduced dialectics into philosophy. Hitherto, dialectics was regarded as a purely subjective method of reasoning. Kant showed that dialectics was neither arbitrary nor subjective, but an entirely valid method of reasoning.
Revolutionary though it was for its time, Kant’s philosophy cannot be regarded as a satisfactory solution to the problems posed by it. More than anything, Kant’s dialectic resembles the old Socratic dialectic of discussion. There is some merit in this. The struggle between opposed conceptions, in which due weight is given to the arguments of the other side, and arguments are put forward for and against in a rigorous way, can lead to a general increase in awareness of the questions involved. Yet there is something unsatisfactory about it; a kind of agnosticism; the superficial idea that "the truth is never all on one side," and so forth.
Kant’s antimonies are only four in number. It was left to Hegel to point out that, in fact everything contains an "antimony" (contradiction):
"That true and positive meaning of the antimonies is this: that every actual thing involves a coexistence of opposed elements. Consequently to know, or, in other words, to comprehend an object is equivalent to being conscious of it as a concrete unity of opposed determinations." (Ibid, p. 78.)
Kant’s merit was to submit the traditional forms of logic to a thoroughgoing criticism. His defect lay in his subjectivist position on the theory of knowledge. This was the source of his main weaknesses— ambiguity, inconsistency and agnosticism. In failing to make a clean break with the traditional logic, while exposing its limitations, Kant landed himself in all kinds of insoluble contradictions (antimonies), which he left unresolved. The problem of the relation between subject and object (thought and being) was only finally resolved by Marx and Engels, who pointed out that, ultimately, all the problems of philosophy are resolved in practice:
"Social life is essentially practical. All mysteries which mislead theory to mysticism find their rational solution in human practice and in the comprehension of this practice." (MESW,Theses on Feuerbach, no. 8, Vol. 1, p. 15.)
Well written. All that is now left are conclusions.