Unfortunately many so-called psychologists seem to consider the concept, even this image-concept, as something fixed in the individual, or at best as only changing with actual experience of the thing conceived. The truth is that the image or images aroused on hearing any word are not the same for two seconds at a time. They are fluid, dynamic; never static, immobile. They are associates of the words in a constant state of flux.[22] When the concept of one individual varies from one moment to the next, how must the concepts of different individuals differ from each other! I have instanced the idea of a horse because it is so simple and concrete. In actual thinking we never meet with a simple separated concept or with a single word; we deal with at least an entire sentence. This means that our images vary even more widely at different times than was the case in the example. It means that the images of other people are at a correspondingly greater variance from ours. As to the application of all this to writing. We have an idea; thinking it important we decide to jot it down. Now we cannot jot down the idea, but only words associated with it. We cannot even write all the words associated with it, for there are too many. So we write a comparative few; and we say we have written the idea. _But all we have really written is something associated with the idea._ When we read this over at a later time we shall not have the same ideas aroused as were in mind originally, but at best only similar ideas. For the associates of words, like all associates, are constantly changing; and thanks to the frailties of human memory exactly the same associates are never aroused twice. So after a long interval they will be much different than at the time we wrote. The reader will often have the experience of “writing a thought” and thinking it very important, but on reading it at another time he will fail to see why he ever considered it worth putting on paper. The truth is that at the time he wrote the idea it probably _was_ important, because he had the right concepts. But when he came back to the words he had written they failed to re-suggest the former concepts and associates.