I didn't say 'strand'. The DNA of twins is identical, consisting only of information, not particular details of a strand, which has properties like position. — noAxioms

Then did you mean the DNA as an abstract thing? In that case, it is a single abstract thing, identical (in every way) to itself. And this abstract thing is instantiated in concrete things - in the concrete DNA strands of the twins. And each of those concrete DNA strands is identical to itself and different from the other, at least with respect to its position in spacetime. Also, each of those concrete DNA strands is different from the abstract DNA.

OK, how about the candle? Are the two states not the same candle because of the differences in lit and burnt-out, or are they one thing, identical to itself, just extended in spacetime? Even the latter has a hard time with identity if you consider MW cloning. The statement "candle is lit at time T" has no truth value if all those states are part of one identity, and only some of those states are 'lit'. — noAxioms

In the usual usage the candle is meant as a thing extended in spacetime (enduring in time). Then the statement "candle is lit at time T" means that the candle is in the lit state at time T.

Anyway, every thing is identical to itself in the sense it is defined. So "candle" as a thing extended in spacetime is identical to itself as a thing extended in spacetime. If by "candle" you mean something else, then this something else must be identical to itself too, in the sense in which it is defined. Otherwise it doesn't exist in that sense - there is no thing in that sense.

Not sure why we're nailing down the usage of identical in this topic. — noAxioms

Existence in the most general sense means being identical to oneself and different from others.

Were the gravitational singularity addressed to be ontically real, however, it of itself would have no context - no not-singularity to which it could be contrasted. Neither entities, such as cats, nor quantities, such as the number seven, would hold presence. — javra

The whole spacetime is present, with the Big Bang singularity presumably at the beginning of the time dimension. And abstract entities like numbers are present even without a spacetime.

The “cosmos” was for the purposes of the argument specifically defined as the “sum of all existents” - and not as merely a collection of things among many others. Then, to state that the context of the sum of all existents is the particular existents themselves is to equivocate both the meaning of “context” and the reasoning first quoted in my previous post. The context of a cat, for example, is not one of its ears. — javra

If by the "sum" you don't mean "collection" or "whole" but all existent things, then the "sum" is not a single thing but many things. And each of those things exists in the context of all the other things.

And if by the "sum" you mean the collection or whole of all existent things then this "sum" is different from each of its parts - because it is not identical to any of its parts, and so the sum is a thing that exists in relation to (or in the "context" of) its parts, which are other things. Anyway, there is no such greatest collection, just as there is no greatest number.

A gravitational singularity from which the Big Bang resulted (this as is modeled by todays mainstream physics) is one such instance of a given with being that is not a thing with context. — javra

If you take a more general definition of "context" you will find that the singularity of the Big Bang does have a context from which it is different. The context can be anything that is not the singularity of the Big Bang, for example my cat (which exists at a different point in spacetime) or number 7 (which transcends every spacetime).

Thus defined, I still find it justifiable to uphold that the cosmos can only exists in terms of being per se but does not exist in terms of a thing with context. — javra

A collection of things (such as a cosmos) is also different from its parts, so the parts provide a context for the collection/whole.

This doesn't help if something is logically consistent but nonexistent. I questioned that above when I cannot come up with an example of a consistent thing that nevertheless is known not to exist. — noAxioms

You cannot come up with an example of a consistent thing that is known not to exist? There is no such example. If existence is logical consistency then every logically consistent thing exists.

About identical, the word is ambiguous. Twins share identical (indistinguishable) DNA but are not the same person. A lit candle seems to share numeric identity with the burnt out stub an hour later. It is the same candle (identical), but the two states are hardly indistinguishable. — noAxioms

When I say that a thing is identical to itself I mean that it is identical in every way. The DNA strands of twins are not identical in every way - to say the least, they have different positions in spacetime, which makes them different things.

I am trying to nail down what we're claiming if we claim something exists or not. — noAxioms

I guess we can agree that every thing that exists must satisfy the criterion of logical consistency: it must be what it is and not be what it is not. In other words, it must be identical to itself and different from what it is not.

I think that in the most fundamental sense, existence is just that. Logical consistency. Then we can talk about various kinds of existence, like spatio-temporal, abstract, mental etc., but these are secondary distinctions.

Causality can be viewed as a special kind of logical relations between entities in the context of the arrow of time, where the consequences logically follow from the causes, and the causes are initial conditions and time-invariant structures known as the laws of physics.