On the other hand, by pushing such fear too far, some fall into the opposite
mistake. ‘Your principles’ they say to the followers of the new science, ‘are not true in an absolute way, therefore your conclusions are not worthy of credit,
and we do not care about them.’
We do not believe that to state that the mathematical method does not have
to be subject to experience is an appropriate answer to this objection.
* Physicists who study the theory of light would avoid a great deal of hard
work, if they could do without having to confirm their deductions through
experience.13 The theory of vibrations in ether tells us that in an anisotropic
elastic environment, every plane wave gives rise to three types of vibrations
parallel to the axes of the polarization ellipsoid. Experience confirms the
existence of two of these types of vibrations, but the third cannot be found.
No geometrician has ever entertained the thought of dominating experience
with his theories. On the contrary, all have looked for ways to change the
theory, in order to obtain exactly what experience provides. This is why the
theory of light is still imperfect, and it would not be surprising if the time
should come when the ether hypothesis were abandoned. But if this hypothesis
is to survive in the world of science, it will only be by having all of its
conclusions justified by experience.
The right answer for those who condemn the new science a priori is to
remark that such an objection could be levelled at any science. Even in
mathematics, the doubt arises whether the three-dimensional space we know
is the only one that exists! The principles of no science are true in an absolute
way, and even if one wishes to argue about this matter, one must discuss
it in general terms, but there is no reason specifically to target Political
Economy.
Value
Object of a theory of value
The real facts which we can observe are the sales of some commodities for
which certain prices are paid. The object of a theory of value cannot consist
in anything but explaining these facts, connecting them, and showing them as
a consequence of one or a few principles.
The empirical path is the one that would lead us to gather a great amount
of data on the prices, to put them together, and to see if it is possible to infer
any law from them. We agree that by using this method, which Mill calls
chemical,14 it is not possible to achieve any truly rational law, although it is
still always very useful to have such data and the empirical laws, which can be
of assistance as a first step in the search for truth.
The geometrical or abstract method15 does not care about those facts; it
sets certain axioms on the nature of men and it infers how the phenomenon
of value must follow. Not even through this path do we believe that it is
possible to achieve the truth; on the contrary, we judge it more fallacious than