POSTULATES I. The human body is composed of a number of individual parts, of diverse nature, each one of which is in itself extremely complex.
II. Of the individual parts composing the human body some are fluid, some soft, some hard.
III. The individual parts composing the human body, and consequently the human body itself, are affected in a variety of ways by external bodies.
IV. The human body stands in need for its preservation of a number of other bodies, by which it is continually, so to speak, regenerated.
V. When the fluid part of the human body is determined by an external body to impinge often on another soft part, it changes the surface of the latter, and, as it were, leaves the impression thereupon of the external body which impels it.
VI. The human body can move external bodies, and arrange them in a variety of ways.
PROPOSITIONS XIV. The human mind is capable of perceiving a great number of things, and is so in proportion as its body is capable of receiving a great number of impressions.
>>>>>Proof—The human body (by Post. iii. and vi.) is affected in very many ways by external bodies, and is capable in very many ways of affecting external bodies. But (II.xii.) the human mind must perceive all that takes place in the human body; the human mind is, therefore, capable of perceiving a great number of things, and is so in proportion, &c. Q.E.D.
XV. The idea, which constitutes the actual being of the human mind, is not simple, but compounded of a great number of ideas.
>>>>>Proof—The idea constituting the actual being of the human mind is the idea of the body (II. xiii.), which (Post. i.) is composed of a great number of complex individual parts. But there is necessarily in God the idea of each individual part whereof the body is composed (II. viii. Cor.); therefore (II. vii.), the idea of the human body is composed of each of these numerous ideas of its component parts. Q.E.D.