BOOK I PART III
To justify still farther this account of the sec-
ond species of probability, where we reason
with knowledge and reflection from a contrari-
ety of past experiments, I shall propose the fol-
lowing considerations, without fearing to give
offence by that air of subtilty, which attends
them. Just reasoning ought still, perhaps, to
retain its force, however subtile; in the same
manner as matter preserves its solidity in the
air, and fire, and animal spirits, as well as in
the grosser and more sensible forms.
First, We may observe, that there is no prob-
ability so great as not to allow of a contrary
possibility; because otherwise it would cease to
be a probability, and would become a certainty.
That probability of causes, which is most ex-
tensive, and which we at present examine, de-
pends on a contrariety of experiments: and it