5. - Adequacy

Summary

In the Ethics, Spinoza speaks of “adequate idea” (idea adequata) and “adequate cause” (causa adequata). Spinoza defines these as follows:

By adequate idea I understand an idea which, insofar as it is considered in itself, without relation to an object, has all the properties, or intrinsic denominations of a true idea. Exp.: I say intrinsic to exclude what is extrinsic, namely, the agreement of the idea with its object.

(E2def4)

I call that cause adequate whose effect can be clearly and distinctly perceived through it. But I call it partial, or inadequate, if its effect cannot be understood through it alone.

(E3def1)

For Spinoza adequate ideas are equivalent to true ideas (E2def4) and to see the connection between adequate causation and adequate ideas we will consider true ideas. A true idea is an idea that agrees with its object (E1a6) and it is also self-presenting in the sense that no one can have a true idea without knowing that it is true (E2p43s) A true idea not only tells how things are or how a thing should be correctly defined but also shows its own truth to the subject who has the idea. The following example, in which Spinoza gives a definition of a sphere, explains this