Now I wonder what it's like for sea stars and sea urchins as they grow from their larval bilateral symmetry to the adult 5-way version, in which everything is also reabsorbed/rearranged to an absurd degree.

It is extremely unlikely that these animals have any sense of self, in which case they would be completely unaware of what's happening to themselves.

Why is it unlikely in your opinion?

It‘s unlikely because decades of experiments suggest so and also because it‘s unlikely that animals with a very basic neural system can have a sense of self. The burden of proof is on those claiming differently.

The burden of proof is on anyone claiming anything because the polarity of propositions is irrelevant to standards of proof, which is why you brought up the studies, because you know that intuitively if not formally.

That's seems backwards. Everything is highly unlikely, a priori. To say that something isn't unlikely is the assertion which requires evidence.

There’s been a lot of research on self identification in many species. One paper I’m aware of did an analysis of 50 years worth of research on over 30 species. So we have a fairly decent idea about the development of theory of mind and self identification in animals. For example self identification has only been found in social animals, and lacking in all the solitary animals studied.

It seems like there’s a progression from simple organisms with sense/response behaviour but little or no cognitive modelling of the environment. Then organisms that can model and reason about their environment in fairly sophisticated ways. Then some animals develop the ability to model the knowledge, intentions and responses of other creatures. That’s what evolutionary psychologists call theory of mind.

Finally there’s development of a sense of self, and then further on the ability to reason about one’s own thoughts, motivations, intentions and cognitive abilities, and act to change those. That’s us. It’s a continuum though, with various species at different points along the line.

I would say, subjectively yes, but these insects are incapable of worrying about that. Furthermore, biologically not quite, because they can reproduce with 100% their original DNA afterwards (unlike offspring which has less and less overlap).

Has it even been proven that insects retain “memories” as we know them? The question always leads back to 1 of 2 options. 1) insects are biological robots and their “instinct” is akin to a program executing code based on the I/O of their senses, or 2) the information required to perform their “instinctual” actions is carried genetically.

Option 1 has significant implications for humanity; are we just more complex machines who believe we’re different (due to a complexity beyond our understanding), but are ultimately just deterministically executing code like a spider? Are we genetically/chemically pre-determined to learn, think, feel and decay the way we do based on the I/O of our lives, and everything we’ve ever done would be repeated identically if we were rebooted and exposed to the exact same I/O (down to the planck unit).

Option 2 indicates more of an inherent “free will”… but even then, are the memories just a more complex form of input, but still inescapably deterministic.

Personally, I believe in determinism — that another universe which started in the EXACT same way (down to the most miniscule detail), exposed to the exact sane external forces (if any) would lead through the EXACT same events to the EXACT same end.

Your 1) and 2) both describe biobots, and neither description relates to memory.

Yeah I think unfortunately it’s just option 1.

Mechanical determinism is actually somewhat orthogonal to free will - a quantum process, for example, is inherently unpredictable, but I don't think that randomness of choices automatically implies free will.

I have no clear conception of what "the insect's perspective" is.