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.
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.