Dutch-Jewish philosopher lived from 1632 to 1677.
Quote: "To my mind, although Spinoza lived and thought long before Darwin, Freud, Einstein, and the startling implications of quantum theory, he had a vision of truth beyond what is normally granted to human beings." /Samuel Shirley, who translated Spinoza's complete works into English.
One of the three great Rationalists, Spinoza's philosophy encompasses nearly every area of philosophical discourse, including metaphysics, epistemology, political philosophy, ethics, philosophy of mind and philosophy of science.

Philosophy of mind/psychology

The human mind

Spinoza argues for a distinct conception of the human mind in Part Two of The Ethics. He says the following:
“ The first thing that constitutes the actual being of a human Mind is nothing but the idea of a singular thing which actually exists.

He then argues that it follows that "the human Mind is a part of the infinite intellect of God."
Further, Spinoza says: "Whatever happens in the object of the idea constituting the human Mind must be perceived by the human Mind"
From this we get a clear rejection of Descartes' mind/body dualism: "The object of the idea constituting the human Mind is the Body, or a certain mode of Extension which actually exists, and nothing else."

Compare Divine Principles, Principle of Creation:

The Human Mind Seen from the Relationship between Spirit Mind and Physical Mind

"The relationship between spirit mind and physical mind is like that between character and form. When these two become one through give and take action centered on God, the spirit man and the physical man naturally become one harmonious unit. The give and take action between the spirit mind and the physical mind produces a united body, the human mind, which directs the individual toward the accomplishment of the purpose of creation. Man became ignorant of God because of the fall. Thus, he became ignorant of the absolute standard of goodness. But, according to the original nature of creation, the human mind always directs man toward what it thinks is good. This directing power is called human conscience. However, fallen man, being ignorant of the absolute standard of goodness, cannot set up the absolute standard of conscience. As the standard of goodness varies, so does the standard of conscience, and this causes frequent contention even among those who advocate a conscientious life. The part of the human mind which corresponds to character and always directs man toward the absolute standard of goodness is called the "original mind", and that which corresponds to form is called the "conscience"."
Ref: Human Mind Seen from the Relationship between Spirit Mind and Physical Mind