A new set because, while class isn't new, the specifics of the class structure are?
BTW: Why "contradiction"? It looks like Marx chose that word in order to make the fall of capitalism look inevitable - it has contradictions, so it must be self-inconsistent, so it must fall, right? But it looks to me that what Marx is describing is just the differences that occur in any society. In what way are they truly contradictions (in the normal sense of the word)?
A new set because history has developed in such a way to generate new contradictions - but yes, the new class structure is at least partially a result of changes in technology (though some Marxists disagree with me on this).
Contradictions doesn't mean internally inconsistent in dialectical sense; Marxism is famous for its application of dialectical logic, in which opposites oppose each other while maintaining unity which must resolve itself, rather than a binary opposition (i.e we must have one or the other) or a binary inclusive-or (which has no potentiality for resolution).
The point of contradictions isn't to say that society will fall because of them (that would be a vulgar reading of the concept and a scientifically untenable one) but rather that any new society must in some way answer to the contradictions, or arise out of their development or increase in intensity. For instance, the contradiction between use-value and exchange-value is only heightened with capitalism, but the contradiction between capital and labour is obviously new with capitalism. By specifying contradictions, they can be thought of (philosophically speaking) and potentially overcome (practically speaking). One such contradiction which has been present in all societies thus far is between freedom and necessity, which Marx claimed would be resolved with the advent of Communism.
I can't speak for the impression Marx wanted to give about the downfall of capitalism from his word choice, but I can say that the dialectical mode of presentation was admitted by Engels to have been rather outmoded even by the time Capital I was published. Contradiction in the dialectical sense doesn't imply inconsistency, it implies the functioning unity of opposites. At best, Marx's use of contradiction implies the possibility to overcome, but I don't know about the necessity. Herbert Marcuse, a renown dialectician, didn't seem to think that the contradiction would be resolved, and Adorno didn't seem to think that the contradiction would resolve positively.
Either way, I'm not going on the defensive here, since Marx's commitment to the scientific method should be reflected in Marxism's ability to be self-critical. Few other "sciences" would be so happy to cast doubt on the logical axioms under which they operate.
Why is there a contradiction between use-value and exchange-value? Exchange-value is just other peoples' use-value (with some exceptions like money itself).
> ... I can say that the dialectical mode of presentation was admitted by Engels to have been rather outmoded even by the time Capital I was published.
Is there a Marxism that doesn't depend on the dialectic? Or just on the dialectical mode of presentation? It has always annoyed me that if you don't believe the dialectic, there seems to be no way to even talk to a Marxist. Am I mistaken?
More generally, it seems to me that Marxists would communicate much more effectively if they used technical words much less in the process of presenting their ideas, at least in non-academic settings. Most people don't want to have to learn a bunch of technical jargon in order to understand the ideas of some group - especially a group that they consider to be not only fringe, but almost certainly already refuted. Few people have enough time to willingly take on such a task.
That's precisely the contradiction. For instance, a house satisfied a social need or want (to keep someone protected from the elements), which is what gives it value to begin with, after all, nothing can have value without first being an object of demand. But strangely, people buy houses to "use" their exchange value, i.e as an asset. Most houses were never designed to be imbued with the sort of labour which makes them valuable as assets, but rather the sort of labour which makes them useful as actual usable homes. In fact, the focus on exchange value means that houses will deteriorate while people collect rent.
Exchange value appears as use-value, but that doesn't make it essentially use-value; while marginalism would say that I sell a product because I "value" (verb) the money more than the product, Marx says that when an object is to be exchanged, I see no use-value in it at all. But of course it has social use-value, because it can fulfill wants and needs.
"The form of use-value is the form of the commodity’s body itself, iron, linen, etc., its tangible, sensible form of existence. This is the natural form (Naturalform) of the commodity. As opposed to this the value-form (Wertform) of the commodity is its social form."
The question Marx wanted to answer was why the actual concrete form of the product appears in the relation to others (for instance, you can't say "20 yards of linen are worth 20 yards of linen", you must say they it is worth "1 coat" or "20 cwt. iron" etc.). The contradiction is that qualitatively different things can be quantitatively the same in value, but this quantitative measurement necessitates a differentiation in quality.
>Thus through the relative value-expression the value of the commodity acquires, first, a form different from its own use-value. The use-form of this commodity is, e.g. linen. But it possesses its value-form in its relation of equality with the coat. Through this relation of equality the body of another commodity, sensibly different from it, becomes the mirror of its own existence as value (Wertsein), of its own character as value (Wertgestalt). In this way it gains an independent and separate value-form, different from its natural form. But second, as a value of definite magnitude, it is quantitatively measured by the quantitatively definite relation or the proportion in which it is equated to the body of the other commodity.
>Is there a Marxism that doesn't depend on the dialectic? Or just on the dialectical mode of presentation?
Yes, John Elster, G.A. Cohen, Roberto Veneziani, Andrew Kliman, Anwar Shaikh, Nobuo Okishio, David Laibman, Naoki Yoshihara and other "analytical Marxists" have at least attempted to either explain Marx and capitalism without such dialectical concepts as value, for instance the theory of hitsorical materialism, or they have attempted to concentrate on the purely quantitative theory of value which can be neatly expressed in neoclassical economic terms (game theory and matrix algebra) to the end of various competing theories which are readable to economists rather than philosophers. The success to which they excise the "mysterious" parts of Marx is up for debate, and I think that a lot is lost in analytical formulations thus far - but the attempts are admirable and perhaps fertile for further research.
I agree with what you're saying on simplicity, but Marx's writings are deep and many-layered and open to several interpretations and re-formulations, to the point where it's hard to speak of him without advancing your favourite interpretation.
So? What came before capitalism? Feudalism. That was a class society at least as much as capitalism is.