For Spinoza, my mind is simply an idea in God’s intellect; in particular it is God’s idea of my body. - Michael Della Rocca

For Spinoza, obviously, the human mind, as well as the human body, are individuals (actually, they are the same individual). However, this individuality of the human mind would be threatened if the human mind were made up of ideas whose contents were relatively disparate, if these ideas were not all focused around a particular unified thing, such as the human body.

According to Spinoza’s system, all reality flows with strict necessity from the nature of God. With the geometrical method, Spinoza captures the structure of this reality by deducing philosophical conclusions about reality from definitions which express the nature of God.

As always with Spinoza, it is helpful to begin with God. The system of ideas that are parallel to modes of extension constitutes God’s infinite intellect.