IIRC, even Feynman refused to answer to whether electrons, or even the interior of a brick, are real, saying that they are useful concepts in our description of the world and that’s all that matters.
That’s not quite what he was saying. Full quote (emphasis mine):
When I sat with the philosophers I listened to them discuss very seriously a book called Process and Reality by Whitehead. They were using words in a funny way, and I couldn’t quite understand what they were saying. Now I didn’t want to interrupt them in their own conversation and keep asking them to explain something, and on the few occasions that I did, they’d try to explain it to me, but I still didn’t get it. Finally they invited me to come to their seminar.
They had a seminar that was like a class. It had been meeting once a week to discuss a new chapter out of Process and Reality — some guy would give a report on it and then there would be a discussion. I went to this seminar promising myself to keep my mouth shut, reminding myself that I didn’t know anything about the subject, and I was going there just to watch.
What happened there was typical — so typical that it was unbelievable, but true. First of all, I sat there without saying anything, which is almost unbelievable, but also true. A student gave a report on the chapter to be studied that week. In it Whitehead kept using the words ‘essential object’ in a particular technical way that presumably he had defined, but that I didn’t understand.
After some discussion as to what ‘essential object’ meant, the professor leading the seminar said something meant to clarify things and drew something that looked like lightning bolts on the blackboard. ‘Mr. Feynman,’ he said, ‘would you say an electron is an “essential object?”’
Well, now I was in trouble. I admitted that I hadn’t read the book, so I had no idea of what Whitehead meant by the phrase; I had only come to watch. ‘But,’ I said, ’I’ll try to answer the professor’s question if you will first answer a question from me, so I can have a better idea of what “essential object” means. Is a brick an essential object?
What I had intended to do was to find out whether they thought theoretical constructs were essential objects. The electron is a theory that we use; it is so useful in understanding the way nature works that we can almost call it real. I wanted to make the idea of a theory clear by analogy. In the case of the brick, my next question was going to be, ‘What about the inside of the brick?’ — and I would then point out that no one has ever seen the inside of a brick. Every time you break the brick, you only see the surface. That the brick has an inside is a simple theory which helps us to understand things better. The theory of electrons is analogous. So I began by asking, ‘Is a brick an essential object?’
Then the answers came out. One man stood up and said, ‘A brick is an individual, specific brick. That is what Whitehead means by an essential object.’ Another man said, ‘No, it isn’t the individual brick that is an essential object; it’s the general character that all bricks have in common — their ‘brickiness’ — that is the essential object.’
Another guy got up and said, ’No, it’s not in the bricks themselves. ‘Essential object’ means the idea in the mind that you get when you think of bricks.’
Another guy got up, and another, and I tell you I have never heard such ingenious different ways of looking at a brick before. And, just like it should in all stories about philosophers, it ended up in complete chaos. In all their previous discussions they hadn’t even asked themselves whether such a simple object as a brick, much less an electron, is an ‘essential object’.
IIRC, even Feynman refused to answer to whether electrons, or even the interior of a brick, are real, saying that they are useful concepts in our description of the world and that’s all that matters.
That’s not quite what he was saying. Full quote (emphasis mine):