BOOK I PART III
The small success, which has been met with
in all the attempts to fix this power, has at last
obliged philosophers to conclude, that the ul-
timate force and efficacy of nature is perfectly
unknown to us, and that it is in vain we search
for it in all the known qualities of matter. In
this opinion they are almost unanimous; and
it is only in the inference they draw from it,
that they discover any difference in their sen-
timents. For some of them, as theCartesians
in particular, having established it as a princi-
ple, that we are perfectly acquainted with the
essence of matter, have very naturally inferred,
that it is endowed with no efficacy, and that it
is impossible for it of itself to communicate mo-
tion, or produce any of those effects, which we
ascribe to it. As the essence of matter consists in
extension, and as extension implies not actual
motion, but only mobility; they conclude, that