The Ethics: Ethica Ordine Geometrico Demonstrata by Benedict de Spinoza and translated from the Latin by R. H. M. Elwes. Ethics, Demonstrated in Geometrical Order (Latin: Ethica, ordine geometrico demonstrata), usually known as the Ethics, is a philosophical treatise written by Benedict de Spinoza. It was written between 1664 and 1665 and was first published in 1677. The book addresses the relationship between God and the universe. Tradition held that God exists outside of the universe, created it for a reason, and could have created a different universe if he so chose.

Spinoza denies each point. According to Spinoza, God is the natural world. The Ethics focuses on the human mind and body. Spinoza attacks several Cartesian positions: (1) that the mind and body are distinct substances that can affect one another; (2) that we know our minds better than we know our bodies; (3) that our senses may be trusted; (4) that despite being created by God we can make mistakes, namely, when we affirm, of our own free will, an idea that is not clear and distinct.