experimental kind, much is left to accurate observation, the object observed is changing, the attention cannot be fixed for long, and the memory is responsible for much. Yet, with trained scientists, mistakes are scarcely taken account of. Suppose, however, that scientists regarded all observation as hopelessly unreliable (which it is if "conscious contents are at the opposite pole from permanent objects"), then all but the single figure experiment which requires no watchful experimenter could be of any value. Hence ordinary scientific observation and experiment would be discountenanced, and, as an indirect result of the absence of practice, the simplest observations and experiments would become unreliable. Furthermore, all inference and verification would be equally ill performed and, therefore, justly held suspect. Of course, the motions of waves in a storm are most difficult to observe accurately, especially from a small boat at the mercy of those waves; but scientific observation is seldom concerned with such problems. If all nature were as unstable as such waves, there would be no more prospect of any physical science, than of an experimental psychology when "conscious contents are at the opposite pole from permanent objects ".
To follow a concrete psychological event—as to follow any event—in its entirety is out of the question, nor, fortunately, has scientific observation anything to do with events in their entirety. Assuming, then, that we may ask of psychologists as much, and no more, as of other scientists, we may go on to inquire whether introspection is practicable or whether the mind is a mad ocean and we inside a small boat in the middle of it, as Wundt contends.
Sir Francis Galton asked a number of persons to observe whether in their thinking they employed imagery. Was it, then, impossible to answer his question because of the furious tossing to and fro of microscopically small ideas? No. Some people definitely stated that no images accompanied their thinking; others that shreds of colourless and indistinct images were observable in their thought; and others still that images which successfully mimicked reality were to be noticed while they were thinking. The records of these observations have never been challenged. Hence we may conclude that images other than words may be recollected and that men differ considerably as to the images which they recall. This is no longer a matter of opinion or of hearsay. It is an established fact, a matter of science. Outlines and colours can be recollected, and this can be shown by 'pure self-observation'.
One need not, however, stop at this point. By the same method of often repeated introspection under varying conditions, one may determine how near to exact reproduction of outlines we may arrive. I may recall the face of a friend, study his recalled features minutely, enter into my notebook all I observe, and compare it with the reality and with former entries. Or I may observe a recalled object which has many and various parts and count and measure off everything, and then again compare it with the original.
