Suppose we were observing the movement of a point (for example, a point of light on a screen). It might be possible to draw important consequences of the most various kinds from the behaviour of this point. And what a variety of observations can be made here!—The path of the point and certain of its characteristic measures (amplitude and wave-length for instance), or the velocity and the law according to which it varies, or the number or position of the places at which it changes discontinuously, or the curvature of the path at these places, and innumerable other things.—Any of these features of its behaviour might be the only one to interest us. We might, for example, be indifferent to everything about its movements except for the number of loops it makes in a certain time.—And if we were interested, not in just one such feature, but in several, each might yield us special information, different in kind from all the rest. This is how it is with the behaviour of man; with different characteristic features which we observe in his behaviour. (PI, p. 179)
In the previous chapters, we have often used the term ‘the Inner’ as a convenient way of referring to our psychological concepts in general. However, the term contains a danger, for it fosters the temptation to see the various elements of the Inner as essentially alike, different components of a homogeneous whole. In fact, our psychological concepts fall into various categories and, within these groups, there are differences as well as similarities. To understand these differences, we must explore the grammar of the concepts, for it is not
enough simply to note that our experiences 133 take a variety of forms. The complexity of the Inner reflects not differences of degree, but differences of concept.