Don't care. The question is, why should anything from physics prefer this particular subset of particles which humans collectively describe as 'pumpkin'?
Depends on what you mean by "from physics?" Obviously, people
do recognize things like pumpkins and even cultures that developed largely in isolation from one another make distinctions that are far more similar than dissimilar. Presumably, the causes behind the emergence and development such distinctions are physical, and the reasons for their being similar are also physical.
Actually, we have a pretty good history of the development of many of these notions. We know how people have probed questions like "what is water?" and "are whales fish?" for millennia. Any explanation of the development of these concepts is going to involve the myriad physical observations people have made of said objects and their careful examination of their physical properties and physical relations vis-á-vis other entities (e.g. through experiments).
Hence, I'd argue that object clearly plays a role in the development of the concepts associated with it, and this role seems to flow from its physical properties and relations. So in that sense, the distinction does come "from physics," and indeed in an ontology like physicalism it seems to be a requirement that all such distinctions can be explained in terms of physics (although perhaps they are not reducible to physics—whether "non-reductive physicalism" is a coherent concept depends on how physicalism is defined).
But if you want an explanation in terms of the subject matter of physics, or in terms of some superveniance vis-á-vis "a set of particles" (which is not necessarily how "physics" would like to define things anyhow) then yes, the object can never be defined "from physics." This doesn't mean that do not objects exist, it means that trying to define them in terms of ensembles of particles won't work. In general, I think the focus on particles as "building blocks," and the desire to define things in terms of them, while quite ancient and still popular, is based on fundamentally flawed assumptions.
So:
Mathematically, any subset is as good as another, so there's no correct answer to 'what one subset of particles is this particle a member?'. Absent a correct answer to that, there doesn't seem to be an objective 'object'.
See:
https://thephilosophyforum.com/discussion/comment/912501
Asking for objects to be defined in terms of sets of particles is like trying to figure out what the letter "a" is, what it does, and how it should be distinguished from other letters/the background, by only looking at the shape of the letter, the pixels that make it up, etc.
I'd argue that the question: "why should anything from physics prefer this particular subset of particles which humans collectively describe as 'pumpkin'?" is simply the wrong sort of question and itself presumes things that I don't think are true— namely that "what things are" is completely a function of "what they are made of." But consider what would happen if you moved a volume of water to a parallel universe with slightly different physical constants. Perhaps "water" as defined as "H2O" can still exist there (if we define H and O based on their atomic numbers), but it might have completely different interactions with everything around it and between parts of itself. For example, a few tweaks get you water where the solid form is denser than the liquid form, which in turn would seem to make life much more difficult to form (an example often given for "fine tuning). But if something has totally different properties, how is it "the same substance?" I would say it isn't; change the fields and you get different things.
All the properties of objects are relational (e.g. lemon peels don't reflect yellow light in a dark room, salt only dissolves in water when placed in salt). Non-relational properties, the properties things have when they interact with nothing else and with no parts of themselves, are, at the very least, epistemicaly inaccessible. Such "in-itself" properties can never make any difference to any possible observer. Hence, Locke made a grave mistake on making "in-itselfness" the gold standard of knowledge, and this culminates in the incoherence of the "view from nowhere." Looking for "what things are" without reference to their relations then is never going to work.
Objects are defined in terms of their relational properties. Things' relationships with minds are often denigrated as somehow "less real" than relations between mindless things. However, I don't think there is much to support such a view. It's based on presuppositions that I think it is difficult to support, and a sort of (often unacknowledged) dualism.
Note that I switched to 'objective' there instead of 'physical', which is dangerous because the word has connotations of 'not subjective' and has little implication of 'not subject to convention'.
:up: Right. That the bishop always moves diagonal is a convention but it's an objective fact. But presumably it's also a fact with physical causes and underpinnings.
I have an autistic son, and such conventions are not so obvious. You point to something, and he's not considering the thing being pointed to. He's looking at the end of your finger, wondering what's there that you're talking about. Not all conventions we find so natural come naturally to someone not neural-normal.
The atypical can only be defined in terms of the typical. That something is "convention" does not make it arbitrary. Barring some sort of libertarianism where man's actions are unconditioned by the way the world is, there is presumably a causal chain behind conventions. And that conventions synch up so well, even when developed in isolation, and that their historical evolution is demonstrably driven by physical examinations of things, I believe demonstrates that the conventions surrounding objects are determined by their properties. I mean, what is the alternative, that conventions re objects don't have
anything to do with objects themselves? Do they spring from the aether then? Presumably something about "tiger" makes it an important distinction for all peoples who encounter tigers to make, in a way that grue or bleen are not.
Perhaps, but your prior post seems to be elevating potency far above act in the analysis. No one uses grue and bleen and I don't imagine you could ever get them to, not least because:
A. It isn't obvious when objects were created by looking at them, smelling them, etc.
B. When an object is "created" is itself a dicey philosophical question.
But you might imagine something like splitting the visible spectrum in half and having words for size AND color for some colors and then shape AND color for others, such that "square + purple" and "yellow + small" are their own discrete words. And yet absolutely no society does this. They use colors and sizes.
It is of course logically possible for conventions to be very many ways. But in actuality they aren't. Presumably, this is not "for no reason at all" and I also see no reason to think it comes from some sort of sui generis and spontaneous uncaused freedom unique to man. Hence, convention cannot be arbitrary but emerges from the interaction between man and the world, something that is presumably "physical" in an important sense and involves the properties of objects in conjunction with human nature and culture.