'There's no such thing as a fish.' So goes the podcast name. The same is true for other things, like seagulls and panthers.
I mean, it's obviously nonsense intuitively, but the slightly pedantic-but-interesting point underlying it is that there is no singular thing in our established animal taxonomies that constitutes a 'fish' or a 'seagull'.
It reminds me of the smart-arse point that peanuts aren't really nuts. Sure, that's true, in that in the botanical domain, 'nut' has a specific meaning to which peanuts do not conform (from memory, they are 'legumes' in this context, but don't quote me on that). But in the naming and referencing of things, we draw a distinction between what constitutes a 'botanical nut' and a 'culninary nut'. And it's usually perfectly clear what we're talking about when we refer to these things outside of specialised domains. ('I told you I was allergic to nuts!'/'Yes, but peanuts are legumes!') Intelligence is knowing that a tomato is a fruit. Wisdom is about knowing not to put one in a fruit salad.
It's all about frames of reference -- the context in which we're referring to a thing. And, perhaps more broadly, the idea that there's some perfect taxonomy that correctly captures and refers to all things, and language is failing when it doesn't adhere to that specific taxonomy, regardless of context. Whereas context is just a huge part of how we communicate, and language without context is worth a whole hell of a lot less.
I'm tired and don't have the time or brain to fully draw connections here -- but this is something that ties up with various things in Ways of Being, and Can draw the lines so neatly as we like them -- the idea of maps and models overtaking a more generalised reality.