CHAPTER III
EMPIRIO-CRITICISM
1. Old and New Positivism. — We must distinguish two
periods in the history of positivism: of these the first
is marked by a dogmatic belief in physical science, which
is set up as the model of every form of knowledge; the
second, dating from about 1870, goes still farther, and
subjects science itself to searching criticism in order to
eliminate any traces of metaphysics which might be
sheltering themselves beneath the cloak of experimental
theories; it no longer looks upon science as an
unchangeable model, but studies the process of formation through
which it passes, and turns to the human organism in its
search for the psycho-physiological basis of this
evolutionary genesis. This latter period approximates less
closely in its methods to the older system of positivism
than it does to the empiricism of David Hume and Stuart
Mill, of which it is the logical conclusion, and which it
completes by the addition of the biological concept of
consciousness and the latest researches of physiological
psychology. While positivism in its earner forms
endeavoured to eliminate metaphysics by proving all
reality to be capable of scientific explanation, taking
refuge in agnosticism when this synthetic effort failed
rather than acknowledge itself beaten by speculation,
the new positive philosophy resorted to a purer and more
ingenuous form of experience than self-styled scientific
experience, and set itself the task of proving the enigmas
of the universe to be non-existent. Metaphysical
