16. The means we employ in order to gain an end may be manifold, may be right or wrong. They are right when they are really adapted to the attainment of the end. The ends, also, even the most essential and final ends, may be manifold. It is a mistake which appeared especially in the eighteenth century, nowadays the tendency is more and more to abandon it, that every one seeks the same end, namely, his own highest possible pleasure.[15] Whoever can believe that the martyr facing with full consciousness the most terrible tortures for the sake of his conviction--and there were some who had no hope of recompense hereafter--was thus inspired by a desire after the greatest possible pleasure, such a man must have either a very defective sense of the facts of the case, or, indeed, have lost all measure of the intensities of pleasure and pain. This, therefore, is certain: even final ends are manifold, between them hovers the choice, which, since the final end is for everything the determining principle, is of the most importance. What ought I to strive after? Which end is the right one, which wrong? This, as Aristotle long ago declared, is the essential, the cardinal question in ethics.[16] 17. Which end is right, for which should our choice declare itself? Where the end is fixed and it is merely a question as to the choice of means, we reply: Choose means which will certainly attain the end. Where it is a question as to the choice of ends we would say: Choose an end which reason regards as really attainable. This answer is, however, insufficient, many a thing attainable is rather to be shunned than sought after; choose the best among attainable ends, this alone is the adequate answer.[17] But the answer is obscure; what do we mean by “the best”? what can be called “good” at all? and how can we attain to the knowledge that one thing is good and better than another? 18. In order to answer this question satisfactorily, we must, above all, inquire into the origin of the conception of the good, which lies, like the origin of all our conceptions, in certain concrete impressions.[18] We possess impressions with _physical_ content. These exhibit to us sensuous qualities localized in space. Out of this sphere arise the conceptions of colour, sound, space and many others. The conception of the good, however, has not here its origin. It is easily recognizable that the conception of the good like that of the true, which, as having affinity, is rightly placed side by side with it, derives its origin from concrete impressions with _psychical_ content.