Appendix I to the first chapter of Ethics: Of God
Of course this is not the place to deduce these things from the nature of the human mind. It will be sufficient here if I take as a foundation what everyone must acknowledge: that all men are born ignorant of the causes of things, and that they all want to seek their own advantage, and are conscious of this appetite. From these [assumptions] it follows, first, that men think themselves free, because they are conscious of their volitions and their appetite, and do not think, even in their dreams, of the causes by which they are disposed to wanting and willing, because they are ignorant of [those causes]. It follows, second, that men act always on account of an end, namely, on account of their advantage, which they want. Hence they seek to know only the final causes of what has been done, and when they have heard them, they are satisfied, because they have no reason to doubt further. But if they cannot hear them from another, nothing remains for them but to turn toward themselves, and reflect on the ends by which they are usually determined to do such things; so they necessarily judge the temperament of the other from their own temperament.
Furthermore, they find—both in themselves and outside themselves—many means that are very helpful in seeking their own advantage, for example, eyes for seeing, teeth for chewing, plants and animals for food, the sun for light, the sea for supporting fish [NS: and so with almost all other things whose natural causes they have no reason to doubt]. Hence, they consider all natural things as means to their own advantage. And knowing that they had found these means, not provided them for themselves, they had reason to believe that there was someone else who had prepared those means for their use. For after they considered things as means, they could not believe that the things had made themselves; but from the means they were accustomed to prepare for themselves, they had to infer that there was a ruler, or a number of rulers, of Nature, endowed with human freedom, who had taken care of all things for them, and made all things for their use.
And since they had never heard anything about the temperament of these rulers, they had to judge it from their own. Hence, they maintained that the gods direct all things for the use of men in order to bind men to them and be held by men in the highest honor. So it has happened that each of them has thought up from his own temperament different ways of worshiping God, so that God might love him above all the rest, and direct the whole of Nature according to the needs of their blind desire and insatiable greed. Thus this prejudice was changed into superstition, and struck deep roots in their minds. This was why each of them strove with great diligence to understand and explain the final causes of all things.
But while they sought to show that Nature does nothing in vain (i.e., nothing not of use to men), they seem to have shown only that Nature and the gods are as mad as men. See, I ask you, how the matter has turned out! Among so many conveniences in Nature they had to find many inconveniences: storms, earthquakes, diseases, and the like. These, they maintain, happen because the gods [NS: (whom they judge to be of the same nature as themselves)] are angry on account of wrongs done to them by men, or on account of sins committed in their worship. And though their daily experience contradicted this, and though infinitely many examples showed that conveniences and inconveniences happen indiscriminately to the pious and the impious alike, they did not on that account give up their long-standing prejudice. It was easier for them to put this among other unknown things, whose use they were ignorant of, and so remain in the state of ignorance in which they had been born, than to destroy that whole construction, and think up a new one.
So they maintained it as certain that the judgments of the gods far surpass man’s grasp. This alone, of course, would have caused the truth to be hidden from the human race to eternity, if mathematics, which is concerned not with ends, but only with the essences and properties of figures, had not shown men another standard of truth. And besides mathematics, we can assign other causes also, which were able to bring it about that men [NS:—but very few in relation to the whole human race—] would notice these common prejudices and be led to the true knowledge of things.
—Baruch Spinoza (1632–1677), Of God – Ethics