A Causal Judgment interprets and explains sense-perceptions. For instance, the tiny baby's first vague notion that something, no knowing what, must have caused the impressions of warmth and whiteness and roundness and smoothness that accompany the arrival of its milk-bottle—this is a causal judgment.

The very first conclusion that you form concerning any sensation that reaches you is that something produced it, though you may not be very clear as to just what that something is. The conclusions of the infant mind, for example, along this line must be decidedly vague and indefinite, probably going no further than to determine that the cause is either inside or outside of the body. Even then its judgment may be far from sure.

Yet, baby or grown-up, young or old, the first effort of every human mind upon the receipt and perception of a sensation is to find out what produced it. The conclusion as to what did produce any particular sensation is plainly enough a judgment, and since it is a judgment determining the cause of the sensation, it may well be termed a causal judgment.

Causal judgments, taken by themselves, are necessarily very indefinite. They do not go much beyond deciding that each individual sensation has a cause, and is not the result of chance on the one hand nor of spontaneous brain excitement on the other. Taken by themselves, causal judgments are disconnected and all but meaningless.

I look out of my window at the red-roofed stone schoolhouse across the way, and, so far as the eye-picture alone is concerned, all that I get is an impression of a flat, irregularly shaped figure, part white and part red. The image has but two dimensions, length and breadth, being totally lacking in depth or perspective. It is a flat, distorted, irregular outline of two of the four sides of the building. It is not at all like the big solid masonry structure in which a thousand children are at work. My causal judgments trace this eye-picture to its source, but they do not add the details of distance, perspective, form and size, that distinguish the reality from an architect's front elevation. These causal judgments of visual perceptions must be associated and compared with others before a real "idea" of the schoolhouse can come to me.

Taken by themselves, then, causal judgments fall far short of giving us that truthful account of the outside world which we feel that our senses can be depended on to convey.

If there were no mental processes other than sense-perceptions and causal judgments, every man's mind would be the useless repository of a vast collection of facts, each literally true, but all without arrangement, association or utility. Our notion of what the outside world is like would be very different from what it is. We would have no concrete "ideas" or conceptions, such as "house," "book," "table," and so on. Instead, all our "thinking" would be merely an unassorted jumble of simple, disconnected sense-perceptions.

What, then, is the process that unifies these isolated sense-perceptions and gives us our knowledge of things as concrete wholes?