Philosophy is not engineering, but neither is computer science, at least not the good bits. But that’s a bit of a sidetrack.
By making new universes I meant defining possible worlds, either on paper, or better yet in executable form. These can be humdrum, such as the world of Minecraft, made up of discrete cubes of material with certain laws of interaction, or much more abstract, like a distributed database system where there is no global clock to give a single unambiguous ordering of events, and it is a struggle to achieve a consistent interpretation of the current state for every observer. Or you can go even higher and try and define a dependent type theory that can unify mathematical proof and executable code, which is what we really need.
The interesting thing about these worlds is that we have direct access to the underlying laws and can address questions of object properties and identity directly. Most of them are not reductionist in the way that the real world is, so you can have a chair that literally exists as an independent object that is not made up of smaller parts, and lots of traditional reasoning about object identity then applies.
If we look at a reductionist universe like Conway’s Life, then I think there is not much to say about objects. The only fundamental entities in this universe are grid cells, and the absolute time step that updates them. Influences can propagate through the grid, and particular patterns of cells might be labelled as “objects” while analysing their behaviour, eg. gliders. But this is for notational convenience, we can’t actually learn anything at the object level that we couldn’t learn by studying the underlying cells.
You can create Turing machines in Life, and then you can analyse them as if they were abstract computing devices, ignoring the grid cells. But if a stray glider crashes into the machine, it will break, and the analysis will fail, just as if a chair in the real world caught fire: at some point your mental model would shift from chair, to burning chair, to smouldering remains of what once was a chair, or just pile of unidentified ash.
So there is clearly not much point for philosophers to debate the fundamental nature of Conway’s Life (right? I am assuming this).
The real world is still less well-defined, and there is behaviour we have not yet explained, and laws we have not fully worked out. But I have to draw the line somewhere, and if someone thinks that a chair has existence independently of the particles that make it up, well I don’t really know what to say to them. I mean, the question of what objects are was answered 2500 years ago by Democritus: arrangements of atoms in the void. Even I know that :)
Since there are no intrinsic properties of objects that can’t be dissolved into statements about their component parts, the only reason to have a theory of objects at all is for convenience in modelling and communication. But both of those have specific requirements, there is no single model of objects that will be ideal for every use case. You are going to need a very different model of chairs depending on whether you are talking to a furniture designer, a cafe owner, a Roomba, or a hunter gatherer.
