Feynman did not like philosophers very much (ironically, his son decided at one point to be one).
In his “Lectures on Physics” (II-16-1) he devotes an entire section to the topic, with the title of “Relativity and the philosophers”. Among other things, he says:
When this idea descended upon the world, it caused a great stir among philosophers, particularly the "cocktail-party philosophers," who say, "Oh, it is very simple: Einstein's theory says all is relative!" In fact, a surprisingly large number of philosophers, not only those found at cocktail parties (but rather than embarrass them, we shall just call them "cocktail-party philosophers"), will say, "That all is relative is a consequence of Einstein, and it has profound influences on our ideas." In addition, they say "It has been demonstrated in physics that phenomena depend upon your frame of reference."
There is another school of philosophers who feel very uncomfortable about the theory of relativity, which asserts that we cannot determine our absolute velocity without looking at something outside, and who would say,
"It is obvious that one cannot measure his velocity without looking outside. It is self-evident that it is meaningless to talk about the velocity of a thing without looking outside; the physicists are rather stupid for having thought otherwise, but it has just dawned on them that this is the case. If only we philosophers had realized what the problems were that the physicists had, we could have decided immediately by brainwork that it is impossible to tell how fast one is moving without looking outside, and we could have made an enormous contribution to physics."
These philosophers are always with us, struggling in the periphery to try to tell us something, but they never really understand the subtleties and depths of the problem.
One of the consequences of relativity was the development of a philosophy which said,
"You can only define what you can measure! Since it is self-evident that one cannot measure a velocity without seeing what he is measuring it relative to, therefore it is clear that there is no meaning to absolute velocity. The physicists should have realized that they can talk only about what they can measure."
“Finally, there is even a philosophy which says that one cannot detect any motion except by looking outside. It is simply not true in physics. True, one cannot perceive a uniform motion in a straight line, but if the whole room were rotating we would certainly know it, for everybody would be thrown to the wall - there would be all kinds of "centrifugal" effects. That the earth is turning on its axis can be determined without looking at the stars, by means of the so-called Foucault pendulum, for example.”
I can certainly feel Feynman’s frustration with some philosophers, talking down to him, without understanding the essence of the relativity theory and the process of acquiring knowledge about natural phenomena.
However, the derisive tone in which he is talking about philosophers in general may reinforce an elitist and dangerous attitude of dismissing all philosophy (and philosophers) as ignorant and stupid.
Feynman hastens to add his own philosophical comments and I could not agree more with what he says:
“What, then, are the philosophic influences of the theory of relativity? If we limit ourselves to influences in the sense of what kind of new ideas and suggestions are made to the physicist by the principle of relativity, we could describe some of them as follows.
The first discovery is, essentially, that even those ideas which have been held for a very long time and which have been very accurately verified might be wrong. It was a shocking discovery, of course, that Newton's laws are wrong, after all the years in which they seemed to be accurate. Of course it is clear, not that the experiments were wrong, but that they were done over only a limited range of velocities, so small that the relativistic effects would not have been evident. But nevertheless, we now have a much more humble point of view of our physical laws - everything can be wrong!
Secondly, if we have a set of “strange” ideas, such as that time goes slower when one moves, and so forth, whether we like them or do not like them is an irrelevant question. The only relevant question is whether the ideas are consistent with what is found experimentalIy. In other words, the “strange ideas” need only agree with experiment, and the only reason that we have to discuss the behavior of clocks and so forth is to demonstrate that although the notion of the time dilation is strange, it is consistent with the way we measure time.
Finally, here is a third suggestion which is a little more technical but which has turned out to be of enormous utility in our study of other physical laws or, more specifically, to look for the ways in which the laws can be transformed and leave their form the same. When we discussed the -theory of vectors, we noted that the fundamental laws of motion are not changed when we rotate the coordinate system, and now we learn that they are not changed when we change the space and time variables in a particular way given by the Lorentz transformation. So this idea of studying the patterns or operations under which the fundamental laws are not changed has proved to be a very useful one.”
However, I would like to go beyond the strictly utilitarian approach and venture into areas of pure speculation. We will never intuitively understand and accept relativity, because, due to our limitations in size, speed and senses, we lack the personal experience with the relativistic world.
Yet, we understand it intellectually, mathematically, and we would like somehow to relate to it emotionally. We know that it means something, but for our lives we can not tell what that something is.
The only thing we can do is speculate.
What kind of reality are we talking about when we accept the relative nature of space and time, mass and energy? What happened to objective reality we assumed to exist, independently of our minds? The very foundation of science had been (until Einstein) the assumption that there is a world out there, with its objective reality, unchanging laws and all we had to do is find out how it was put together.
We fancied ourselves as the curious tinkerer who stumbles upon an intriguing machine and, by studying its workings and the visible parts of the mechanism, wants to understand how it functions and what its purpose is.
We could not approach this task without the assumption that the machine is always the same: what was true yesterday is still true today; what was true for me it is also true for everyone else. These were the absolutes we expected from the subject of our investigation.
And then suddenly Einstein comes along and tells us that we were all wrong, there are no absolutes, what appears to one person, may look completely different to another, it all depends on how and from where we look at things.
Or did Einstein say that? Did he abolish all the absolutes in our universe, or demolished some, left some others and created new ones?
If there are still absolutes in the universe after Einstein finished with it then, maybe, we ‘worshipped’ the wrong ‘gods’ (absolutes) and now we have to recognize our mistake and start paying homage to the true ‘gods’ instead?