Spinoza's Ethics: II.A3: Affects

Spinoza precedes A3 with A2 - that humans think. Here in A3, he begins discussing modes of thinking with what we call "feelings." Spinoza posits that affectus or what I am translating as "change" is a thinking mode. The "changes" described here occur due to representational modes of thinking or "ideas." In this framework, "John loves Mary" means that "John has a mode of thinking which is a change or affectus due to a mode of thinking which is a representation thought or idea of Mary." Both terms - affectus or "changes"  and ideae or "ideas" indicate modes of thinking but one is of variation and the other is of representation. Further, variation cannot exist without representation.

Language note: Affectus is the same term for different noun cases and numbers. It can be nominative or genitive singular as well as nominative or accusative plural. This adds to the general translation challenges presented by Latin's lack of definite and indefinite articles. Here Spinoza is using the genitive singular to indicate a genitive of description in "name of change."

Our popular usage splits "feelings" from "thoughts." We view "feelings" as emotional reactions of our hearts, while we view "thoughts" as activities of our minds. Spinoza considers both of these concepts of feelings and thoughts as modes of thinking. He does indicate that a "change" modes of thinking must be accompanied by an "idea" mode of thinking. This introduces a tool of the mind: by removing the idea of a thing, one is able to remove the related change. This "out of sight, out of mind" approach is helpful as some changes can be troubling to an individual.

Conversely, an individual may have an "idea" mode of thinking but not have an accompanying change mode of thinking. This indicates that the idea itself may be present without triggering a change. Using the example above, it is possible for John to have a mode of thinking which is a representational thought or idea of Mary without a related mode of thinking that is a change or affectus." If the idea of Mary is troubling to John but he is not able to use an "out of sight, out of mind" approach, then he may seek to find way to have the idea of Mary without such idea causing a change.

Modi cogitandi ut amor, cupiditas vel quicunque nomine affectus animi insigniuntur, non dantur nisi in eodem individuo detur idea rei amatæ, desideratæ etc. At idea dari potest quamvis nullus alius detur cogitandi modus. 

Translated as,

Modes of thinking are designated by the name of a change of mind such as love, desire or whatsoever, are not given unless the idea of the thing loved, desired etc is given in the same individual. But the idea [of the thing loved, desired etc.] may exist although no other mode of thinking exists.