On the Improvement of Understanding, by Benedict de Spinoza, [1883], at sacred-texts.com
[12] (1) I will here only briefly state what I mean by true good, and also what is the nature of the highest good. (2) In order that this may be rightly understood, we must bear in mind that the terms good and evil are only applied relatively, so that the same thing may be called both good and bad according to the relations in view, in the same way as it may be called perfect or imperfect. (3) Nothing regarded in its own nature can be called perfect or imperfect; especially when we are aware that all things which come to pass, come to pass according to the eternal order and fixed laws of nature.
[13] (1) However, human weakness cannot attain to this order in its own thoughts, but meanwhile man conceives a human character much more stable than his own, and sees that there is no reason why he should not himself acquire such a character. (2) Thus he is led to seek for means which will bring him to this pitch of perfection, and calls everything which will serve as such means a true good. (13:3) The chief good is that he should arrive, together with other individuals if possible, at the possession of the aforesaid character. (4) What that character is we shall show in due time, namely, that it is the knowledge of the union existing being the mind and the whole of nature. [c]
[14] (1) This, then, is the end for which I strive, to attain to such a character myself, and to endeavor that many should attain to it with me. (2) In other words, it is part of my happiness to lend a helping hand, that many others may understand even as I do, so that their understanding and desire may entirely agree with my own. (3) In order to bring this about, it is necessary to understand as much of nature as will enable us to attain to the aforesaid character, and also to form a social order such as is most conducive to the attainment of this character by the greatest number with the least difficulty and danger.
[15] (1) We must seek the assistance of Moral Philosophy [d] and the Theory of Education; further, as health is no insignificant means for attaining our end, we must also include the whole science of Medicine, and, as many difficult things are by contrivance rendered easy, and we can in this way gain much time and convenience, the science of Mechanics must in no way be despised.
[16] (1) But before all things, a means must be devised for improving the understanding and purifying it, as far as may be at the outset, so that it may apprehend things without error, and in the best possible way. (2) Thus it is apparent to everyone that I wish to direct all science to one end [e] and aim, so that we may attain to the supreme human perfection which we have named; and, therefore, whatsoever in the sciences does not serve to promote our object will have to be rejected as useless. (3) To sum up the matter in a word, all our actions and thoughts must be directed to this one end.