Affect (philosophy) - in Spinoza

In Spinoza

In Spinoza's Ethics, Part III Definition 3, the term "affect" (affectus, traditionally translated as "emotion") is the modification or variation produced in a body (including the mind) by an interaction with another body which increases or diminishes the body's power of activity (potentia agendi):

By affect I understand affections of the body by which the body's power of acting is increased or diminished, aided or restrained, and at the same time, the ideas of these affections.

Affect is thus a special case of the more neutral term "affection" (affectio), which designates the form "taken on" by some thing, the mode, state or quality of a body's relation to the world or nature (or infinite "substance"). In Part III, "Definitions of the Emotions/Affects", Spinoza defines 48 different forms of affect, including love and hatred, hope and fear, envy and compassion. They are nearly all manifestations of the three basic affects of:

• desire (cupiditas) or appetite (appetitus), defined as "the very essence of man insofar as his essence is conceived as determined to any action from any given affection of itself";
• pleasure (laetitia), defined as "man's transition from a state of less perfection to a state of greater perfection"; and
• pain or sorrow (tristitia), defined as "man's transition from a state of greater perfection to a state of less perfection".

In Spinoza's view, since God's power of activity is infinite, any affection which increases the organism's power of activity leads to greater perfection. Affects are transitional states or modes in that they are vital forces by which the organism strives to act against other forces which act on it and continually resist it or hold it in check.