simple is the sole producer of wealth, and that labour is productive in
proportion to the hours devoted to it, how has it happened--this is our
crucial question--that the amount of labour which produced seven at one
period should produce thirty-three at another? How are we to explain the
presence of the additional twenty-six?

The answer of Marx, and of those who reason like him, is that, owing to
the development of knowledge, mechanical and chemical especially, and
the consequent development of industrial methods and machinery, labour
as a whole has itself become more productive. But to say this is merely
begging the question. To what is this development of knowledge, of
methods, and of machinery due? Is it due to such labour as that of the
"untirable human animals," to which Mill refers as an example of labour
in its intensest form? In a word, does ordinary labour, or the
industrial effort of the majority, contain in itself any principle of
advance at all?

We must, in order to do justice to any theory, consider not only the
points on which its exponents lay the greatest stress, but also those
which they recognise as implied in it, or which we may see to be implied
in it ourselves. And if we consider the theory of Marx in this way, we
shall see that labour, in the sense in which he understands the word,
does contain principles of advance which are of two distinguishable
kinds.

One of these is recognised by Marx himself. Just as, when he says that
labour is the sole productive agency, he assumes the gifts of nature,
which provide it with something to work upon, so, when he conceives of
labour as the effort of hand and muscle, he assumes a human mind behind
these by which hand and muscle are directed. Such being the case, he