pSYCHO-ANALYSIS was born from medical
practice, and its theories are mainly psychological,
but it stands in close relation to two other branches
of learning—biology and the science of society.
It is perhaps one of its chief merits that it forges
another link between these three divisions of the science
of man. The psychological views of Freud—his
theories of conflict, repression, the unconscious, the
formation of complexes—form the best elaborated part
of psycho-analysis, and they cover its proper field.
The biological doctrine—the treatment of sexuality and
of its relation to other instincts, the concept of the
' libido ' and its various transformations—is a part of
thetheory which is much less finished, less free from
contradictions and lacunae, and which receives more
criticism, partly spurious and partly justified. The
sociological aspect, which most interests us here, will
deserve more attention. Curiously enough, though
sociology and anthropology have contributed most