So that according to their notion of the act, considered with regard
to its consequences, these following things are all essential to it:
viz., That it should be necessary, and not necessary; that it should
be from a cause, and no cause; that it should be the fruit of choice
and design, and not the fruit of choice and design; that it should be
the beginning of motion or exertion, and yet consequent on previous
exertion; that it should be before it is; that it should spring
immediately out of indifference and equilibrium, and yet be the effect
of preponderation; that it should be self-originated, and also have
its original from something else; that it is what the mind causes
itself, of its own will, and can produce or prevent according to its
choice or pleasure, and yet what the mind has no power to prevent,
precluding all previous choice in the affair.
So that an act, according to their metaphysical notion of it, is
something of which there is no idea.... If some learned philosopher
who had been abroad, in giving an account of the curious observations
he had made in his travels, should say he had been in Tierra del
Fuego, and there had seen an animal, which he calls by a certain name,
that begat and brought forth itself, and yet had a sire and dam
distinct from itself; that it had an appetite and was hungry, before
it had a being; that his master, who led him and governed him at his
pleasure, was always governed by him and driven by him where he
pleased; that when he moved he always took a step before the first
step; that he went with his head first, and yet always went tail
foremost; and this though he had neither head nor tail: it would be no
impudence at all to tell such a traveler, though a learned man, that
he himself had no idea of such an animal as he gave an account of, and
never had, nor ever would have.