The outward impression upon the senses, together with the mood which it alone awakens in us, vanishes with the presence of the thing. Therefore these two cannot of themselves constitute _experience_ proper, whose teaching is to guide our conduct for the future. The image of that impression which the imagination preserves is originally weaker than the impression itself, and becomes weaker and weaker daily, until in time it disappears altogether. There is only one thing which is not subject either to the instantaneous vanishing of the impression or to the gradual disappearance of its image, and is therefore free from the power of time. This is the _conception_. In it, then, the teaching of experience must be stored up, and it alone is suited to be a safe guide to our steps in life. Therefore Seneca says rightly, “_Si vis tibi omnia subjicere, te subjice rationi_” (Ep. 37). And I add to this that the essential condition of surpassing others in actual life is that we should reflect or deliberate. Such an important tool of the intellect as the _concept_ evidently cannot be identical with the _word_, this mere sound, which as an impression of sense passes with the moment, or as a phantasm of hearing dies away with time. Yet the concept is an idea, the distinct consciousness and preservation of which are bound up with the word. Hence the Greeks called word, concept, relation, thought, and reason by the name of the first, ὁ λογος. Yet the concept is perfectly different both from the word, to which it is joined, and from the perceptions, from which it has originated. It is of an entirely different nature from these impressions of the senses. Yet it is able to take up into itself all the results of perception, and give them back again unchanged and undiminished after the longest period of time; thus alone does _experience_ arise. But the concept preserves, not what is perceived nor what is then felt, but only what is essential in these, in an entirely altered form, and yet as an adequate representative of them. Just as flowers cannot be preserved, but their ethereal oil, their essence, with the same smell and the same virtues, can be. The action that has been guided by correct conceptions will, in the result, coincide with the real object aimed at. We may judge of the inestimable value of conceptions, and consequently of the reason, if we glance for a moment at the infinite multitude and variety of the things and conditions that coexist and succeed each other, and then consider that speech and writing (the signs of conceptions) are capable of affording us accurate information as to everything and every relation when and wherever it may have been; for comparatively _few_ conceptions can contain and represent an infinite number of things and conditions. In our own reflection _abstraction_ is a throwing off of useless baggage for the sake of more easily handling the knowledge which is to be compared, and has therefore to be turned about in all directions.