word, cognition)
are nothing but different forms of attention; similarly the emotions, the
appetites, and the will, nothing but modifications of desire; while both
alike take their origin in sensation. Sensation is the sole source and the
sole content of the life of the mind as a whole. To prove these positions
Condillac makes use of the fiction of a statue, in which one sense awakes
after another, first the lowest of the senses, smell, and last the most
valuable, the sense of touch, which compels us (by its perception of
density or resistance) to project our sensations, and thus wakes in us the
idea of an external world. In themselves sensations are merely subjective
states, modes of our own being; without the sense of touch we would ascribe
odor, sound, and color to ourselves. Condillac distinguishes between
sensation and _ideas_ in a twofold sense, as mere ideas (the memory or
imagination of something not present), and as ideas of objective things
(the image, representative of a body); this latter sense is meant when he
says, touch sensations only are also ideas.

For the details of the deduction, which often makes very happy use of a
rich store of psychological material, the reader must be referred to the
more extended expositions. Here we can only cite as examples the chief
among the genetic definitions. Perceptions (impressions) and consciousness
are the same thing under different names. A lively sensation, in which the
mind is entirely occupied, becomes attention, without the necessity of
assuming an additional special faculty in the mind. Attention, by its
retentive effect on the sensation, becomes memory. Double attention--to
a new sensation, and to the lingering trace of the previous one--is
comparison; the recognition of a relation (resemblance or difference)
between two ideas is judgment; the separation of an idea from another
naturally connected with it, by the aid of voluntary linguistic symbols,
is abstraction; a series of judgments is reflection; and the sum total of
inner phenomena, that wherein ideas succeed one another, the ego or person.
All truths concern relations among ideas. The tactual idea of solidity
accustoms us to project the sensations of the other senses also, to
transfer them thither where they are not; hence arise the ideas of our
body, of external objects, and of space. If we perceive several such
projected qualities together, we refer them to a substratum--substance,
which we know to ex