which he emancipates himself from the tutelage of Locke
and treats psychology in his own characteristic way. He had been led, he
tells us, partly by the criticism of a talented lady, Mademoiselle
Ferrand, to question Locke's doctrine that the senses give us intuitive
knowledge of objects, that the eye, for example, judges naturally of
shapes, sizes, positions and distances. His discussions with the lady
had convinced him that to clear up such questions it was necessary to
study our senses separately, to distinguish precisely what ideas we owe
to each sense, to observe how the senses are trained, and how one sense
aids another. The result, he was confident, would show that all human
faculty and knowledge are transformed sensation only, to the exclusion
of any other principle, such as reflection. The plan of the book is that
the author imagines a statue organized inwardly like a man, animated by
a soul which has never received an idea, into which no sense-impression
has ever penetrated. He then unlocks its senses one by one, beginning
with smell, as the sense that contributes least to human knowledge. At
its first experience of smell, the consciousness of the statue is
entirely occupied by it; and this occupancy of consciousness is
attention. The statue's smell-experience will produce pleasure or pain;
and pleasure and pain will thenceforward be the master-principle which,
determining all the operations of its mind, will raise it by degrees to
all the knowledge of which it is capable. The next stage is memory,
which is the lingering impression of the smell-experience upon the
attention: "memory is nothing more than a mode of feeling." From memory
springs comparison: the statue experiences the smell, say, of a rose,
while remembering that of a carnation; and "comparison is nothing more
than giving one's attention to two things simultaneously." And "as soon
as the statue has comparison it has judgment." Comparisons and judgments
become habitual, are stored in the mind and formed into series, and thus
arises the powerful principle of the association of ideas. From
comparison of past and present experiences in respect of their
pleasure-giving quality arises desire; it is desire that determines the
operation of our faculties, stimulates the memory and imagination, and
gives rise to the passions. The passions, also, are nothing but
sensation transformed. These indications will suffice to show the
general course of the argument in