So much for the essentials of the cognitive relation where the knowledge is conceptual in type, or forms knowledge ‘about’ an object.  It consists in intermediary experiences (possible, if not actual) of continuously developing progress, and, finally, of fulfilment, when the sensible percept which is the object is reached.  The percept here not only verifies the concept, proves its function of knowing that percept to be true, but the percept’s existence as the terminus of the chain of intermediaries creates the function.  Whatever terminates that chain was, because it now proves itself to be, what the concept ‘had in mind.’

The towering importance for human life of this kind of knowing lies in the tact that an experience that knows another can figure as its representative, not in any quasi-miraculous ‘epistemological’ sense, but in the definite, practical sense of being its substitute in various operations, sometimes physical and sometimes mental, which lead us to its associates and results.  By experimenting on our ideas of reality, we may save ourselves the trouble of experimenting on the real experiences which they severally mean.  The ideas form related systems, corresponding point for point to the systems which the realities form; and by letting an ideal term call up its associates systematically, we may be led to a terminus which the corresponding real term would have led to in case we had operated on the real world.  And this brings us to the general question of substitution.

What, exactly, in a system of experiences, does the ‘substitution’ of one of them for another mean?

According to my view, experience as a whole is a process in time, whereby innumerable particular terms lapse and are superseded by others that follow upon them by transitions which, whether disjunctive or conjunctive in content, are themselves experiences, and must in general be accounted at least as real as the terms which they relate.  What the nature of the event called ‘superseding’ signifies, depends altogether on the kind of transition that obtains.  Some experiences simply abolish their predecessors without continuing them in any way.  Others are felt to increase or to enlarge their meaning, to carry out their purpose, or to bring us nearer to their goal.  They ‘represent’ them, and may fulfil their function better than they fulfilled it themselves.  But to ’fulfil a function’ in a world of pure experience can be conceived and defined in only one possible way.  In such a world transitions and arrivals (or terminations) are the only events that happen, tho they happen by so many sorts of path.  The only function that one experience can perform is to lead into another experience; and the only fulfilment we can speak of is the reaching of a certain experienced end.  When one experience leads to (or can lead to) the same end as another, they agree in function.  But the whole system of experiences as they are immediately given presents itself as a quasi-chaos through which one can pass out of an initial term in many directions and yet end in the same terminus, moving from next to next by a great many possible paths.