11. The qualities which make our complex ideas of substances depend mostly on external, remote, and
unperceived causes.
Had we such ideas of substances as to know what real constitutions produce those sensible
qualities we find in them, and how those qualities flowed from thence, we could, by the specific ideas of their real
essences in our own minds, more certainly find out their properties, and discover what qualities they had or had
not, than we can now by our senses: and to know the properties of gold, it would be no more necessary that gold
should exist, and that we should make experiments upon it, than it is necessary for the knowing the properties of a
triangle, that a triangle should exist in any matter, the idea in our minds would serve for the one as well as the
other. But we are so far from being admitted into the secrets of nature, that we scarce so much as ever approach
the first entrance towards them. For we are wont to consider the substances we meet with, each of them, as an
entire thing by itself, having all its qualities in itself, and independent of other things; overlooking, for the most
part, the operations of those invisible fluids they are encompassed with, and upon whose motions and operations
depend the greatest part of those qualities which are taken notice of in them, and are made by us the inherent
marks of distinction whereby we know and denominate them. Put a piece of gold anywhere by itself, separate
from the reach and influence of all other bodies, it will immediately lose all its colour and weight, and perhaps
malleableness too; which, for aught I know, would be changed into a perfect friability. Water, in which to us
fluidity is an essential quality, left to itself, would cease to be fluid. But if inanimate bodies owe so much of their
present state to other bodies without them, that they would not be what they appear to us were those bodies that
environ them removed; it is yet more so in vegetables, which are nourished, grow, and produce leaves, flowers,
and seeds, in a constant succession. And if we look a little nearer into the state of animals, we shall find that their
dependence, as to life, motion, and the most considerable qualities to be observed in them, is so wholly on
extrinsical causes and qualities of other bodies that make no part of them, that they cannot subsist a moment
without them: though yet those bodies on which they depend are little taken notice of, and make no part of the
complex ideas we frame of those animals. Take the air but for a minute from the greatest part of living creatures,
and they presently lose sense, life, and motion. This the necessity of breathing has forced into our knowledge. But
how many other extrinsical and possibly very remote bodies do the springs of these admirable machines depend
on, which are not vulgarly observed, or so much as thought on; and how many are there which the severest
inquiry can never discover? The inhabitants of this spot of the universe, though removed so many millions of
miles from the sun, yet depend so much on the duly tempered motion of particles coming from or agitated by it,
that were this earth removed but a small part of the distance out of its present situation, and placed a little further
or nearer that source of heat, it is more than probable that the greatest part of the animals in it would immediately
perish: since we find them so often destroyed by an excess or defect of the sun's warmth, which an accidental
position in some parts of this our little globe exposes them to. The qualities observed in a loadstone must needs
have their source far beyond the confines of that body; and the ravage made often on several sorts of animals by
invisible causes, the certain death (as we are told) of some of them, by barely passing the line, or, as it is certain of
other, by being removed into a neighbouring country; evidently show that the concurrence and operations of
several bodies, with which they are seldom thought to have anything to do, is absolutely necessary to make them
be what they appear to us, and to preserve those qualities by which we know and distinguish them. We are then
quite out of the way, when we think that things contain within themselves the qualities that appear to us in them;
and we in vain search for that constitution within the body of a fly or an elephant, upon which depend those
qualities and powers we observe in them. For which, perhaps, to understand them aright, we ought to look not
only beyond this our earth and atmosphere, but even beyond the sun or remotest star our eyes have yet discovered.
For how much the being and operation of particular substances in this our globe depends on causes utterly beyond
our view, is impossible for us to determine. We see and perceive some of the motions and grosser operations of
things here about us; but whence the streams come that keep all these curious machines in motion and repair, how
conveyed and modified, is beyond our notice and apprehension: and the great parts and wheels, as I may say so,
of this stupendous structure of the universe, may, for aught we know, have such a connexion and dependence in
their influences and operations one upon another, that perhaps things in this our mansion would put on quite
another face, and cease to be what they are, if some one of the stars or great bodies incomprehensibly remote from
us, should cease to be or move as it does. This is certain: things, however absolute and entire they seem in
themselves, are but retainers to other parts of nature, for that which they are most taken notice of by us. Their
observable qualities, actions, and powers are owing to something without them; and there is not so complete and
perfect a part that we know of nature, which does not owe the being it has, and the excellences of it, to its
neighbours; and we must not confine our thoughts within the surface of any body, but look a great deal further, to
comprehend perfectly those qualities that are in it.