[geye1234]

It's both discovery and experiment (but not invention). Forms are real, but not in the way Plato thought. He thought they existed in some empyrean realm. In reality, they exist in objects themselves. We discover what a thing's form is by experimenting with (or on) it. Aristotle was largely right.

The big philosophical problem with much of this is that people assume that the smallest things are the most fundamental. So people think that stuff, whatever that stuff is, is fundamentally made up of much smaller stuff, and that stuff is fundamentally made of yet smaller stuff, and so the smaller you get, the more fundamental you get. And so (they think) if you want to work out what is really going on at any layer of reality, you need to figure out what the smallest possible things are.

Yet this is ultimately a philosophical posit -- it's not empirically-informed. There's no good reason for thinking it.

To be clear, none of this is about physicists doing physics. It's about the philosophy that many people bring into, and therefore take away from, these kinds of discussions.

[kayo_20211030]

I found the reference. It was an interview with Freeman Dyson where he said "quarks were invented", and I don't think it's a slip of the tongue.

It's at 3:17 in this video of an interview with him https://www.youtube.com/watch?v=hV41QEKiMlM

It's representative of a view that there's a thing (a particle) that explains another thing (a force) that was consistent with both theory and experiment. Thus, a quark could be a particle, and it was whatever the experimentalists and theorists said it was, however it was measured or contemplated.

For a deeper meaning it becomes an exercise in hermeneutics i.e what does it mean when we say "particle"? That was the point of the original piece - there is no uncontested view of a particle's form, should one even exist. Each field, in order to advance, finds it useful to interpret it, or think about it, in different ways.