the two
alternatives: either that God created the world for the sake of men's
pleasure and eyesight, or else that He created men's pleasure and
eyesight for the sake of the world. _From a letter to Hugo Boxel_
(1674).

SECOND PART

ON MAN

_The more things the mind knows, the better it understands its own
powers and the order of Nature. The better it understands its own
powers, so much the more easily can it direct itself and propose rules
to itself. The better, also, it understands the order of Nature, the
more easily can it restrain itself from what is useless._

SPINOZA.

CHAPTER IX

THE NATURE AND ORIGIN OF THE HUMAN MIND

_Introductory_

I pass on now to explain those things which must necessarily follow from
the essence of God or the Being eternal and infinite; not indeed to
explain all these things, for we have demonstrated that an infinitude of
things must follow in an infinite number of ways,--but to consider those
things only which may conduct us, as it were, by the hand to a knowledge
of the human mind and its highest happiness.

_Definitions_

I. By body, I understand a mode which expresses in a certain and
determinate manner the essence of God in so far as He is considered as
the thing extended.

II. I say that to the essence of anything pertains that, which being
given, the thing itself is necessarily posited, and being taken away,
the thing is necessarily taken; or, in other words, that, without which
the thing can neither be nor be conceived, and which in its turn cannot
be nor be conceived without the thing.

III. By idea, I understand a conception of the mind which the mind forms
because it is a thinking thing.

_Explanation._--I use the word conception rather than perception because
the name perception seems to indicate that the mind is passive in its
relation to the object. But the word conception seems to express the
action of the mind.

IV. By adequate idea, I understand an idea which, in so far as it is
considered in itself, without reference to the object, has all the
properties or internal signs (_denominationes intrinsecas_) of a true
idea.

_Explanation._--I say internal, so as to exclude that which is external,
the agreement, namely, of the idea with its object.

V. Duration is the indefinite continuation of existence.

_Explanation._--I call it indefinite because it cannot be determined by
the nature itself of the existing thing nor by the efficien