问答题 There are a great many reasons for studying what philosophers have said in the past. One is that we cannot separate the history of philosophy from that of science. Philosophy is largely discussion about matters on which few people are quite certain, and those few hold opposite opinions. As knowledge increases, philosophy buds off the sciences.
We also see how every philosopher reflects the social life of his day. 1 But we can hardly guess what the world will look like to men and women with several generations of communism behind them, who take the brotherhood of man for granted, not as an ideal to be aimed at, but a fact of life, and yet know that this brotherhood was only achieved by ghastly struggles.
The study of philosophies should make our own ideas flexible. We are all of us apt to take certain general ideas for granted, and call them common sense. We should learn that other people have held quite different ideas, and that our own have started as very original guesses of philosophers.
If a dog could speak, it would probably not distinguish between motion and life. Some primitive men do not do so, and travelers interpret them as saying there are spirits everywhere. 2 In our age of machines we are apt to look for mechanical explanations of everything, yet it is only three hundred years since machines had been developed so far that Descartes first suggested that animal and human bodies were machines.
A scientist is apt to think that all the problems of philosophy will ultimately be solved by science. I think this is true for a great many of the questions on which philosophers still argue. 3 For example, Plato thought that when we saw something, one ray of light came to it from the sun, and another from our eyes, and that seeing was something like feeling with a stick. We now know that the light comes from the sun, and is reflected into our eyes. We don"t know in much detail how the changes in our eyes give rise to sensation. 4 But there is every reason to think that we learn more about the physiology of the brain, we shall do so, and that the great philosophical problems about knowledge and will are going to be pretty fully cleared up.
5 But if our descendants know the answers to these questions and others which perplex us today, there will still be one field of which they do not know, namely the future. However exact our science, we cannot know it as we know the past. Philosophy may be described as argument about things of which we are ignorant. And where science gives us a hope of knowledge it is often reasonable to suspend judgment. That is one reason why Marx and Engels quite rightly wrote so little on many philosophical problems which interested their contemporaries.