it thus that matter presents itself?

_A priori_ we may presume that our perception manages to apprehend
matter with this bias. Sensory organs and motor organs are in fact
coordinated with each other. Now, the first symbolize our faculty of
perceiving, as the second our faculty of acting. The organism thus
evidences, in a visible and tangible form, the perfect accord of
perception and action. So if our activity always aims at a _result_ into
which it is momentarily fitted, our perception must retain of the
material world, at every moment, only a _state_ in which it is
provisionally placed. This is the most natural hypothesis. And it is
easy to see that experience confirms it.

From our first glance at the world, before we even make our _bodies_ in
it, we distinguish _qualities_. Color succeeds to color, sound to sound,
resistance to resistance, etc. Each of these qualities, taken
separately, is a state that seems to persist as such, immovable until
another replaces it. Yet each of these qualities resolves itself, on
analysis, into an enormous number of elementary movements. Whether we
see in it vibrations or whether we represent it in any other way, one
fact is certain, it is that every quality is change. In vain, moreover,
shall we seek beneath the change the thing which changes: it is always
provisionally, and in order to satisfy our imagination, that we attach
the movement to a mobile. The mobile flies for ever before the pursuit
of science, which is concerned with mobility alone. In the smallest
discernible fraction of a second, in the almost instantaneous perception
of a sensible quality, there may be trillions of oscillations which
repeat themselves. The permanence of a sensible quality consists in this
repetition of movements, as the persistence of life consists in a series
of palpitations. The primal function of perception is precisely to grasp
a series of elementary changes under the form of a quality or of a
simple state, by a work of condensation. The greater the power of acting
bestowed upon an animal species, the more numerous, probably, are the
elementary changes that its faculty of perceiving concentrates into one
of its instants. And the progress must be continuous, in nature, from
the beings that vibrate almost in unison with the oscillations of the
ether, up to those that embrace trillions of these oscillations in the
shortest of their simple perceptions. The first feel hardly anything but
movements;