d in time to perish, would be to reason
inconsistently or absurdly. This is the view of nature that I would wish
philosophers to take; but, there are certain prejudices of education or
prepossession of opinion among them to be overcome, before they can be
brought to see those fundamental propositions,--the wasting of the land,
and the necessity of its renovation by the co-operation of the mineral
system. Let us then consider how men of science, in examining the
mineral state of things, and reasoning from those appearances by which
we are to learn the physiology of this earth, have misled themselves
with regard to physical causes, and formed certain mineralogical and
geological theories, by which their judgment is so perverted, in
examining nature, as to exclude them from the proper means of correcting
their first erroneous notions, or render them blind to the clearest
evidence of any other theory that is proposed.

When men of science reason upon subjects where the ideas are distinct
and definite, with terms appropriated to the ideas, they come to
conclusions in which there is no difference of opinion. It is otherwise
in physical subjects, where things are to be assimilated, in being
properly compared; there, things are not always compared in similar and
equal circumstances or conditions; and there, philosophers often draw
conclusions beyond the analogy of the things compared, and thus judge
without data. When, for example, they would form the physical induction,
with regard to the effect of fire or water upon certain substances in
the mineral regions, from the analogy of such events as may be observed
upon the surface of the earth, they are apt to judge of things acting
under different circumstances or conditions, consequently not producing
similar effects; in which case, they are judging without reason, that
is, instead of inductive reasoning from actual data or physical truth,
they are forming data to themselves purely by supposition, consequently,
so far as these, imagined data may be wrong, the physical conclusion, of
these philosophers may be erroneous.

It is thus that philosophers have judged, with regard to the effects of
fire and water upon mineral substances below the bottom of the sea,
from what their chemistry had taught them to believe concerning bodies
exposed to those agents in the atmosphere or on the surface of the
earth. If in those two cases the circumstances were the same, or
similar, consequently