It’s not even that we lack a way to define fish, it’s more that we lack a definition that isn’t arbitrary. One can define them as something like “vertebrates, except for all these ones that we don’t want to include”, but then there’s not really a clear reason to exclude all the amphibians and reptiles and mammals and such, other than that they don’t traditionally get called fish. Some of them even live in water, and a handful of fish can leave the water to a limited extent, so it isn’t even that.
When it’s a grouping that we lack the definition for, then the group doesn’t really exist, even if it’s members do and we all gave a good idea of what are, for instance, fish. Basically the group ‘fish’ contains all the things you think are fish, which is problematic as someone else may have a different idea of which things belong in the group, and while that’s fine when talking coloquially, you can’t really use it when trying to discuss things in a rigerous fashion.
We don’t lack a definition, we actually just have so many narrower definitions that we don’t need one for “fish” anymore. The old, broad definitions become archaic and often inaccurate as we gain more knowledge.
Just because we lack a definition, doesn’t mean something doesn’t exist.
It’s not even that we lack a way to define fish, it’s more that we lack a definition that isn’t arbitrary. One can define them as something like “vertebrates, except for all these ones that we don’t want to include”, but then there’s not really a clear reason to exclude all the amphibians and reptiles and mammals and such, other than that they don’t traditionally get called fish. Some of them even live in water, and a handful of fish can leave the water to a limited extent, so it isn’t even that.
So you are saying Pluto is a fish?
When it’s a grouping that we lack the definition for, then the group doesn’t really exist, even if it’s members do and we all gave a good idea of what are, for instance, fish. Basically the group ‘fish’ contains all the things you think are fish, which is problematic as someone else may have a different idea of which things belong in the group, and while that’s fine when talking coloquially, you can’t really use it when trying to discuss things in a rigerous fashion.
The vast majority of language is not “rigorous”. Colloquial definitions are incredibly important.
Which is fine as long as you don’t try to make rigid distinctions out of your arbitrary colloquia and claim to be acting logically.
You can make distinctions based on similar “fuzzy” definitions, as long as you allow room for inevitable exceptions.
Yes.
We don’t lack a definition, we actually just have so many narrower definitions that we don’t need one for “fish” anymore. The old, broad definitions become archaic and often inaccurate as we gain more knowledge.