What makes good philosophy?
Three things in my view:
⁃ Explains what it’s supposed to and with as few mysteries as possible
⁃ Doesn’t contradict or undermine itself or have logical mistakes
⁃ Doesn’t lead to absurdities
The first point is self-explanatory, which means it passes its own test 🙂
How about the third point, avoiding absurdity? In practice, there is no such thing as a normal idea. All ideas lead to some strangeness and absurdities. But absurdity is relative and depends on your sense of what’s plausible. So saying that cats are really cats is better than saying that cats could be dogs, but that is not as bad as saying that cats must be pieces of cheese.
What philosophy lets you do is examine any idea and clearly see where all the lines are – its strengths and weaknesses, the ideas it is related to and the weirdness it leads to. After that it is a judgment call about whether you can accept the weirdness in order to get the good stuff.
Is nominalism bad philosophy?
To summarise my previous post: Nominalism is the idea that we can’t know what things are, and how you “carve up” reality is simply convention with no basis in fact. So cats could be cats, or they could be dogs, or they could be pieces of cheese.
Nominalism arguably fails all three tests:
⁃ It doesn’t explain anything. Instead it unexplains and leads to radical scepticism about everything. It makes the success of science a miracle. I don’t know how you could argue that we can’t know what a cat is but we can do quantum physics.
⁃ It undermines itself. I don’t know how you could argue that we can’t know what a cat is but we can understand high-faluting philosophical ideas such as nominalism. Also can we even say “nominalism is true” if nominalism undermines the very idea of truth?
⁃ It can lead to absurdities although given the above discussion on absurdities this is not its weakest point.
Even though the majority of modern philosophers are nominalists, no one walks around calling themselves a nominalist. I think this is because nominalism is not at the core of their philosophy, it’s more of a side issue. So they have their core philosophical ideas that inevitably lead to nominalism, and they’ve made the judgment call that their core ideas are good enough that it doesn’t matter, they can just assume that cats are cats rather than proving it and get on with their lives.
But this makes nominalism a bit like that strange cousin that no one wants to talk to at Christmas dinner. Nobody likes nominalism but if your core ideas require it it’s hard to get rid of.
Everyone has to make judgment calls like that. It comes down to what you think is plausible and what you don’t.