cartesian corpuscular physics      In cartesian corpuscular physics, after which Ethica's exposition {2a2.1} to {2L07} is molded, the extended universe is an infinite space of bodies, with sizes and positions, liable to be pushed by, other bodies. Al mechanics is by direct contact (pushing, collision). Euclidian geometry is the mathematical theory of sizes and positions, the Euclidian axiomatic presentation of is used as a model for the exposition in Ethica. A few decades later cartesian physics was generally abandoned in favour of Newton's classical particle mechanics which featured fields of gravity through which the bodies' masses can attract (pull) each other at a distance. Newton retained Euclidian geometry to map physical space. Yet later another mapping got adopted.

cartesian product                          Spinoza's idea of attributes as infinite spaces is related to a method of geometry of Descartes, centuries later formally defined under the name cartesian product. An example of a graphical representation of a cartesian product is the horizontal and vertical line you draw by way of coordinate system before drawing a line representing a mathematical function. To understand a geometrical figure, I need to understand it is in an  infinite space, say a geometrical plane, in which it is drawn. When someone draws a geometrical figure, you are asked to take the sheet of paper, blackboard or sand surface it is drawn for that infinite space. In Ethica, all limited things (res, modi) are in only one such a geometrical space called attribute of which it is claimed there must be an infinite number, but human beings sense only two disjunct ones (having no common element): extension and thought. Ethica claims to prove geometrically that of the human being, who is a mind and a body in unity (unita), the body-part is only liable to (Cartesian) impacts ("hits" literally) from other modi in the its own Cartesian product-space called attribute of extension. The mind, being part of in the attribute of thinking is only liable to impacts from modi of the attribute of thinking. But these two attributes themselves do not make impacts on each other, nor can any element of one make in impact on an element of the other. Nevertheless, and this is the Spinoza-problem, elsewhere we read that the human mind perceives the body, and perception is a passion (which means an impact from a res externa) (More in getting started)

pineal gland                                  According to Descartes the pineal gland (a gland in the human brain, now known to be an endocrine gland producing the hormone melatonin) is the principal seat of the soul.