If a student understands the functional relation between the variables, then he/she should be able to answer the following thought experiments.

After a discussion of this "functional relation" he asserts that:

Psychophysics deals with functional relations between the mind and physical phenomena.

A rating curve is the functional relation between stage and discharge.

Young children, from late infancy to early childhood, understand functional relations.

Coordinate the functional relations with the different members of the National Intelligence System.

They therefore investigate causal and functional relations within and between these levels.

In fact, one can see that all of your behavioral as well as functional relations to colors will be the same.

But they are nevertheless able to agree that it is sometimes possible to elaborate functional relations of the sort we have considered.

But the underlying functional relations between the four parts remain the same.