oming, even spiritual becoming. But there are
metaphysical reasons also. Descartes had naively solved the anthropological
problem by the answer that the interaction of mind and body is
incomprehensible but actual. The occasionalists had hesitatingly questioned
these conclusions a little, the incomprehensibility as well as the
actuality, only at last to leave them intact. For the explanation that
there is a real influence of body on mind and _vice versa_, though not
an immediate but an occasional one, one mediated by the divine will, is
scarcely more than a confession that the matter is inexplicable. Spinoza,
who admits neither the incognizability of anything real, nor any
supernatural interferences, roundly denies both. There is no intercourse
between body and soul; yet that which is erroneously considered such
is both actually present and explicable. The assumed interaction is as
unnecessary as it is impossible. Body and soul do not need to act on one
another, because they are not two in kind at all, but constitute one being
which may be looked at from two different sides. This is called body when
considered under its attribute of extension, and spirit when considered
under its attribute of thought. It is quite impossible for two substances
to affect each other, because by their reciprocal influence, nay, by their
very duality, they would lose their independence, and, with this, their
substantiality. There is no plurality of substances, but only one, the
infinite, the divine substance. Here we reach the center of the system.
There is but one becoming and but one independent, substantial being.
Material and spiritual becoming form merely the two sides of one and the
same necessary world-process; particular extended beings and particular
thinking beings are nothing but the changeable and transitory states
_(modi)_ of the enduring, eternal, unified world-ground. "Necessity in
becoming and unity of being," mechanism and pantheism--these are the
controlling conceptions in Spinoza's doctrine. Multiplicity, the
self-dependence of particular things, free choice, ends, development, all
this is illusion and error.

%(a) Substance, Attributes, and Modes%.--There is but one substance, and
this is infinite (I. _prop_. 10, _schol; prop_. 14, _cor_. 1). Why, then,
only one and why infinite? With Spinoza as with Descartes independence is
the essence of substantiality. This is expressed in the third definition:
"By substance I understan