Species

78 Species

is a series of lectures given before the Royal Society, including his general overview
of botany (“vegetables”—Grew is primarily interested in crop plants), An idea of a
philosophical history of plants, given on January 8, and January 15, 1672.

[12. §.] For in looking upon divers Plants, though of different Names and Kinds; yet if

some afnity may be found betwixt them, then the Nature of any one of them being

well known, we have thence ground of conjecture, as to the Nature of all the rest.

So that as every Plant may have somewhat of Nature individual to it self; so, as far

as it obtaineth any Visible Communities with other Plants, so far, may it partake of

Common Nature with those also.^130

In short, Grew is arguing that if we can identify the nature of one kind, we can
expect that others will share in it to the extent that they share an “afnity” with it.
Nature is here a kind of inductive warrant, because genera share their own prop-
erties, and kinds will therefore also share the generic properties. He expands on
this later, noting that if we know the essence of a plant (the causes of its being and
becoming what it is) we can know what is necessary to it, and what is accidental—
based on its internal structure as well as its outward appearance:

20. §. From all which, we may come to know, what the Communities of Vegetables are,
    as belonging to all; what their Distinctions, to such a Kind; their Properties, to such
    a Species; and their Peculiarities, to such Particular ones. And as in Metaphysical, or
    other Contemplative Matters, when we have a distinct knowledge of the Communities
    and Differences of Things, we may then be able to give their true Definitions: so we
    may possibly, here attain, to do likewise: not only to know, That every Plant Inwardly
    differs from another, but also wherein; so as not surely to Dene by Outward Figure
    than by the Inward Structure. What that is, or those things are, whereby any Plant, or
    Sort of Plants, may be distinguished from all others. And having obtained a knowledge
    of the Communities and Differences amongst the Parts of Vegetables; it may conduct
    us through a Series of more facile and probable Conclusions, of the ways of their
    Causality, as to the Communities and Differences of Vegetation.^131

Thus, essence for Grew is a matter of causally efcacious internal microstructure,
which we would now regard as a natural kind. This makes him one of the few actual
material essentialists we shall encounter in the history of biology before the nine-
teenth century.^132 He employs the Aristotelian denitional approach, naturally, but
treats the denitions as identifying the true causes, the “active capacitating Causes,”
of the nature of the plants.

53. §. The prosecution of what is here proposed, will be requisite, To a fuller and
    clearer view, of the Modes of Vegetation, of the Sensible Natures of Vegetables, and
    of their more Recluse Faculties and Powers. First, of the Modes of Vegetation. For
    suppose we were speaking of a Root; from a due consideration of the Properties

(^130) Grew 1682, 6.
(^131) Grew 1682, 10.
(^132) Material but not taxonomic, as he is not concerned with plant taxonomy but physiology (anatomy).