Potentia names the power to act and produce effects through a being’s nature in Spinoza. God’s power being identical with essence and the limited powers of finite things belong to one natural order, without being powers of the same scale. Humans form no independent empire within nature.
Power is not an abstract possibility held in reserve. It becomes intelligible through encounters and combinations. Nourishment, cooperation, or learning may change what someone can do; such examples illustrate its relational character without reducing it to contemporary measures of welfare.
Affectus concerns bodily and ideational changes that increase or diminish this power; conatus concerns striving to persevere. Striving, power, and the character of a change address different questions and should not be substituted for one another.
In the political writings, the relation between power and right opens an inquiry into the combination of human powers. Potentia and potestas do not form a mechanically consistent dictionary opposition in every passage. This entry primarily follows the framework of the Ethics.