s
completely extended in space as our senses and intellect represent it.

We have treated of the first point elsewhere. As to the second, we will
limit ourselves to pointing out that perfect spatiality would consist in
a perfect externality of parts in their relation to one another, that is
to say, in a complete reciprocal independence. Now, there is no material
point that does not act on every other material point. When we observe
that a thing really is there where it _acts_, we shall be led to say (as
Faraday[79] was) that all the atoms interpenetrate and that each of them
fills the world. On such a hypothesis, the atom or, more generally, the
material point, becomes simply a view of the mind, a view which we come
to take when we continue far enough the work (wholly relative to our
faculty of acting) by which we subdivide matter into bodies. Yet it is
undeniable that matter lends itself to this subdivision, and that, in
supposing it breakable into parts external to one another, we are
constructing a science sufficiently representative of the real. It is
undeniable that if there be no entirely isolated system, yet science
finds means of cutting up the universe into systems relatively
independent of each other, and commits no appreciable error in doing so.
What else can this mean but that matter _extends_ itself in space
without being absolutely _extended_ therein, and that in regarding
matter as decomposable into isolated systems, in attributing to it quite
distinct elements which change in relation to each other without
changing in themselves (which are "displaced," shall we say, without
being "altered"), in short, in conferring on matter the properties of
pure space, we are transporting ourselves to the terminal point of the
movement of which matter simply indicates the direction?

What the _Transcendental Aesthetic_ of Kant appears to have established
once for all is that extension is not a material attribute of the same
kind as others. We cannot reason indefinitely on the notions of heat,
color, or weight: in order to know the modalities of weight or of heat,
we must have recourse to experience. Not so of the notion of space.
Supposing even that it is given empirically by sight and touch (and Kant
has not questioned the fact) there is this about it that is remarkable
that our mind, speculating on it with its own powers alone, cuts out in
it, _a priori_, figures whose properties we determine _a priori_:
experience,