Benedict de Spinoza, THE ETHICS
Page: 10

human mind, is the idea of some particular thing actually
existing.

>>>>>Proof--The essence of man (by the Cor. of the last Prop.) is
constituted by certain modes of the attributes of God, namely
(by II. Ax. ii.), by the modes of thinking, of all which (by II.
Ax. iii.) the idea is prior in nature, and, when the idea is
given, the other modes (namely, those of which the idea is prior
in nature) must be in the same individual (by the same Axiom).
Therefore an idea is the first element constituting the human
mind. But not the idea of a non-existent thing, for then (II.
viii. Cor.) the idea itself cannot be said to exist; it must
therefore be the idea of something actually existing. But not of
an infinite thing. For an infinite thing (I. xxi., xxii.), must
always necessarily exist; this would (by II. Ax. i.) involve an
absurdity. Therefore the first element, which constitutes the
actual being of the human mind, is the idea of something actually
existing. Q.E.D.

<<<<the infinite intellect of God; thus when we say, that the human
mind perceives this or that, we make the assertion, that God has
this or that idea, not in so far as he is infinite, but in so far
as he is displayed through the nature of the human mind, or in
so far as he constitutes the essence of the human mind; and when
we say that God has this or that idea, not only in so far as he
constitutes the essence of the human mind, but also in so far as
he, simultaneously with the human mind, has the further idea of
another thing, we assert that the human mind perceives a thing
in part or inadequately.

*****Note--Here, I doubt not, readers will come to a stand, and
will call to mind many things which will cause them to hesitate;
I therefore beg them to accompany me slowly, step by step, and
not to pronounce on my statements, till they have read to the
end.

XII. Whatsoever comes to pass in the object of the idea, which
constitutes the human mind, must be perceived by the human mind,
or there will necessarily be an idea in the human mind of the