XLVII. If of our own proper genus, we know nothing with certainty, what
must our knowledge be of others? The genus most immediately next to our
own, is that of plants, and in this, notwithstanding our proximity, we
can discern nothing but our ignorance; for we cannot venture even by
conjectures, to point out the constitutive difference between them.
This is not only invisible to the eyes of evidence, but impalpable to
the essays of opinion. We commonly define the genus of a plant, by the
term insensible living entity. But the word insensible, which we use
to describe the difference, only signifies want of sensibility; and
a positive entity, such as a plant is, cannot be ascertained by a
negative. Besides this, as we observed before, it is somewhat doubtful,
whether plants are, or are not sensible. We call them also _living
vegetables_. But by this idea, we do not assign to the plant a different
nature from the animal, for that this also is a living vegetable. If I
am told, that the difference consists, in that the life of the animal
is vegetative and sensitive, and that that of the plant is purely
vegetative, I reply, that the adverb _purely_ in this place, signifies
nothing but the want of sensitive life, which is meant to be expressed
in the extreme, and a want, cannot be made use of as a descriptive term,
to point out the constitutive difference between positive entities.
Nor will it be of any use to answer, that the term want, means a want
or defect in the mode of explanation, and does not apply to the thing
signified; for till it can be ascertained what the thing signified is,
we must remain totally in the dark; and it is also false, that this
term _want_, is not applicable to the thing signified; for negative
expressions are positive with respect to the thing signified, when they
are used to deny any imperfection in the object they relate to; for
the want of an imperfection, is the want of a want, it being certain,
that all imperfection consists in the want of positive perfection;
for which reasons these words, infinity, immensity, indivisibility,
although negative with respect to the mode of expression, are positive
with respect to the thing signified; but the term insensible, or
insensibility, applied to a plant, signifies want of perfection, and thus
is negative with respect to the thing signified.
XLVIII. Besides this, some express a doubt, whether plants are
vegetable or not; and some are also doubtful, whether the property
of vegetation does not likewise belong to stones and metals. If we
consult the Cartesians upon this point, they will tell us, that all we
call vegetation or nutrition of plants, is pure mechanism, and that
the attraction of the nutritious juice which we attribute to them,
is a solemn chimera. If we forsake the Cartesians, and apply to the
experimental philosophers, we shall find many of them, who will tell us,
that metals and stones grow by means of vegetation; which is an opinion,
that not long ago, was illustrated by Joseph Pitton de Tournfort, a
celebrated naturalist of the Academy Royal of Sciences at Paris, and
more especially, by the celebrated observations he made upon marble in
the wonderful cave of Antiparos; and with respect to metals, we, to the
authority of others, shall add that of Aristotle, who in his book _de
Mirabilibus Auscultationibus_, says, that in a territory of the island
of Cyprus, they were used to sow iron, and that it grew and vegetated
like other plants.
XLIX. And now we are speaking of Aristotle, we will not omit mentioning
an authority of his, which is very applicable to our present subject,
because it is totally opposite to a received opinion in the schools,
to wit, that plants and animals are of two different genuses, and that
the distinction between them is, that the animal is a living sensible
entity, and the plant a living insensible one. Aristotle in his book _de
Plantis_ says, that oysters and other shell-fish, are both plants and
animals: _scimus autem, quod conchyla animalia sunt cognitione carentia:
quapropter plantæ sunt, & animalia_. I ask now, how one species can be
classed under two diametrically opposite genuses? and how an oyster
can be both sensible and insensible? for as an animal, it ought to be
a living sensible entity, and as a plant, a living insensible one. Nor
can it be said, that Aristotle, when he called an oyster a plant, spoke
in a metaphorical sense, for this mode of speaking is not allowed to
philosophers, but is only permitted to poets and orators. Besides, the
cause he assigns, shews, that he spoke in a rigorous philosophical sense;
although, to speak the truth, I do not comprehend who could reveal to
Aristotle, that oysters and other shell-fish are destitute of that sort
of knowledge, which is proper and natural to the most stupid brutes.