Reason as an Idea
Spinoza’s characterization of ideas of reason in Ethics 2 makes reason distinctive both psychologically and epistemologically. Psychologically, ideas of reason are frequently present to mind and, as a result, powerful influences on human belief and action; a notable class of ideas of reason, the common notions, are always present to mind. Within such ideas we always regard certain properties to be present in the objects of our experience. Epistemologically, ideas of reason are a distinctively human kind of knowledge, where we cannot immediately know the essences of singular things, as on many views gods or angels might. Instead, in the first instance, rational knowledge is knowledge of properties of things in experience. From such knowledge, Spinoza argues, we can also come to further knowledge by means of processes, and it is these processes that closely resemble what many readers today will recognize as reasoning.