not discoverers--inventors. No man ever made a discovery (he may have
stumbled on one) without the exercise of as much imagination as,
employed in another direction and in alliance with other faculties,
would have gone to the creation of a poem. Every one who has seriously
investigated a novel question, who has really interrogated Nature with
a view to a distinct answer, will bear me out in saying that it
requires intense and sustained effort of imagination. The relations of
sequence among the phenomena must be seen; they are hidden; they can
only be seen mentally; a thousand suggestions rise before the mind, but
they are recognised as old suggestions, or as inadequate to reveal what
is sought; the experiments by which the problem may be solved have to
be imagined; and to imagine a good experiment is as difficult as to
invent a good fable, for we must have distinctly PRESENT--clear mental
vision--the known qualities and relations of all the objects, and must
see what will be the effect of introducing some new qualifying agent.
If any one thinks this is easy, let him try it: the trial will teach
him a lesson respecting the methods of intellectual activity not
without its use. Easy enough, indeed, is the ordinary practice of
experiment, which is either a mere repetition or variation of
experiments already devised (as ordinary story-tellers re-tell the
stories of others), or else a haphazard, blundering way of bringing
phenomena together, to see what will happen. To invent is another
process. The discoverer and the poet are inventors; and they are so
because their mental vision detects the unapparent, unsuspected facts,
almost as vividly as ocular vision rests on the apparent and familiar.

It is the special aim of Philosophy to discover and systematise the
abstract relations of things; and for this purpose it is forced to
allow the things themselves to drop out of sight, fixing attention
solely on the quality immediately investigated, to the neglect of all