Spinoza’s treatise titled Ethics was published in 1677. It is written in a style similar to Euclid’s Elements; Spinoza first defines key terms, then provides axioms, and then derives conclusions from those axioms.
In Part II, Spinoza identifies God with Nature. He claims that God is an extended thinking thing, and that all bodies and ideas flow from God. ‘Extension and Thought’/‘Body and Mind’, according to Spinoza, are two different expressions of the same thing. For example, a circle drawn on a piece of paper and the idea of a circle are different expressions of the same thing – a circle.
Spinoza also claims that free will does not exist and that everything occurs in a deterministic way according to God. Spinoza argues that this doctrine “tranquilizes our spirit and shows us where our highest happiness or blessedness is, namely, solely in the knowledge of God.”
I found Spinoza’s writing style to be tedious at times. The proofs that he provides for each proposition contain many references to other definitions, axioms, and postulates; this forces the reader to refer back to cited passages and therefore break the natural flow of reading. It renders the text more difficult to comprehend. In A History of Western Philosophy, Bertrand Russell advises people to merely read Spinoza’s propositions; I agree with Russell’s recommendation.
“God is a thinking thing. God is an extended thing.”
“The first element, which constitutes the actual being of the human mind, is the idea of some particular thing actually existing.”
“It is not in the nature of reason to regard things as contingent, but as necessary.”
“The human mind has an adequate knowledge of the eternal and infinite essence of God.”
“In the mind there is no absolute or free will; but the mind is determined to wish this or that by a cause, which has also been determined by another cause, and this last by another cause, and so on to infinity.”
“It teaches us to act solely according to the decree of God, and to be partakers in the Divine nature, and so much the more, as we perform more perfect actions and more and more understand God. Such a doctrine not only completely, tranquillizes our spirit, but also shows us where our highest happiness or blessedness is, namely, solely in the knowledge of God, whereby we are led to act only as love and piety shall bid us. We may thus clearly understand, how far astray from a true estimate of virtue are those who expect to be decorated by God with high rewards for their virtue, and their best actions, as for having endured the direst slavery; as if virtue and the service of God were not in itself happiness and perfect freedom.”
“It teaches us, how we ought to conduct ourselves with respect to the gifts of fortune, or matters which are not in our own power, and do not follow from our nature. For it shows us, that we should await and endure fortune’s smiles or frowns with an equal mind, seeing that all things follow from the eternal decree of God by, the same necessity, as it follows from the essence of a triangle, that the three angles are equal to two right angles.”
“It teaches us to hate no man, neither to despise, to deride, to envy, or to be angry, with any. Further, it tells us that each should be content with his own, and helpful to his neighbour, not from any womanish pity, favour, or superstition, but solely by the guidance of reason, according as the time and occasion demand.”
“It teaches how citizens should be governed and led, not so as to become slaves, but so that they may freely do whatsoever things are best.”