Tuesday, November 17, 2009

George Plekhanov: Dialectic and Logic

The philosophy of Marx and Engels is not only a materialist philosophy, it is dialectical materialism. Two objections are, however, raised against this doctrine. We are told, first of all, that dialectic itself is not proof against criticism; and, secondly, that materialism is incompatible with dialectic. Let us examine these objections.

The reader will probably remember how Bernstein explained what he termed the “errors” of Marx and Engels. They were due, he said, to the disastrous influence of dialectic. Customary logic holds fast to the formula: “Yes is yes, and no is no”; whereas dialectic has a formula of a diametrically opposite kind: “Yes is no, and no is yes.” Detesting this latter formula, Bernstein declares that it leads us into temptation and involves us in the most dangerous errors.

Probably most readers who pass by the name of “educated” will agree with Bernstein, seeing that, on the face of it, the formula “Yes is no, and no is yes” is in flagrant contradiction with the fundamental and immutable laws of thought. That is the aspect of the question we have now to examine.

The fundamental laws of logic are three in number:

(I) The law of identity;

(2) The law of contradiction;

(3) The law of the excluded middle.

The law of identity (principium identitatis) declares: A is A (omne subjectum est praedicatum sui), or A=A.

The law of contradiction, A is not not-A, is nothing more than the negative form of the first law.

According to the law of the excluded middle (principium exclusi tertii), two contradictory propositions, mutually exclusive, cannot both of them be true. In fact, either A is B, or else A is not B. If one of these propositions is true, the other is necessarily false; and conversely. There is not, and cannot be, any middle course here.

Ueberweg points out that the law of contradiction and the law of the excluded middle can be unified in the following logical rule: To every definite question, understood in a definite sense, as to whether a given characteristic attaches to a given object, we must reply either yes or no; we cannot answer yes and no.

It is certainly hard to raise any objection to this. But if the statement is true, that implies that the formula “Yes is no, and no is yes” must be erroneous. Nothing will be left for us, then, but to laugh, like Bernstein, and to raise our hands to heaven, when we see that thinkers as profound as Heraclitus, Hegel and Marx have found it more satisfying than the formula “Yes is yes, and no is no,” a formula solidly based upon the three fundamental laws of thought stated above.

This conclusion, fatal to dialectic, seems irrefutable. But, before we accept it, let’s examine the matter more closely.

The movement of matter underlies all the phenomena of nature. But what is movement? It is an obvious contradiction. Should any one ask you whether a body in motion is at a particular spot at a particular time, you will be unable, with the best will in the world, to answer In accordance with Ueberweg’s rule, that is to say in accordance with the formula, “Yes is yes, and no is no.” A body in motion is at a given point, and at the same time it is not there. We can only consider it in accordance with the formula “Yes is no, and no is yes.” This moving body thus presents itself as an irrefutable argument in favor of the “logic of contradiction”; and one who is unwilling to accept this logic will be forced to proclaim, with Zeno, that motion is merely an illusion of the senses.

But of all those who do not deny motion we shall ask: “What are we to think of this fundamental law of thought which conflicts with the fundamental fact of being? Must we not treat it with some circumspection?”

We seem to be between the horns of a dilemma. Either we must accept the fundamental laws of formal logic and deny motion; or else we must admit motion and deny these laws. The dilemma is certainly a disagreeable one. Let us see if there is no way of escaping it.

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