The scholastic philosophers naturally held dualistic
views resulting from their extreme devotion to formalism. This blind
dualism found its natural consequence in the revolt of the Renaissance
thinkers, Bruno and Paracelsus, who asserted the unity of mind and
matter in all existence and were the precursors of the more intelligent
monism of Leibnitz and the scientific metaphysics of his successors. The
birth of modern physical science on the other hand in the investigations
of Bacon and Descartes obscured the metaphysical issue by the
predominance of the mechanical principles of natural philosophy. They
attempted to explain the fundamental problems of existence by the
unaided evidence of the new natural science. Thus Descartes maintained
the absolute dualism of the _res cogitans_ and the _res extensa_.
Spinoza realized the flaw in the division and preferred to postulate
behind mind and matter a single substance (_unica substantia_) while
Leibnitz explained the universe as a harmony of spiritual or
semispiritual principles. Kant practically abandons the problem. He
never really establishes a relation between pure reason and
things-in-themselves (_Dinge an sich_), but rather seeks refuge in a
dualism within consciousness, the transcendental and the empirical.
Since Kant there are, therefore, two streams of dualism, dealing, one
with the radical problem of the relation between mind and matter, the
other with the relation between the pure rational and the empirical
elements within consciousness. To the first problem there is one obvious
and conclusive answer, namely that matter in itself is inherently
unthinkable and comes within the vision of the mind only as an
intellectual presentation. It follows that philosophy is in a sense both
dualist and monist; it is a cosmic dualism inasmuch as it admits the
possible existence of matter as a hypothesis, though it denies the
possibility of any true knowledge of it, and is hence in regard of the
only possible knowledge an idealistic monism. It is a self-destructive
dualism, a confessedly one-sided monism, agnostic as to the fundamental
problem. To the second problem there are two main answers, that of
Associationism which denies to the mind any _a priori_ existence and
asserts that sensation is the only source of knowledge, and that which
admits the existence of both transcendental and empirical knowledge.

DUALLA, one of the principal negro peoples of Cameroon estuary, West