I don't know what the first entity was. I will never know. What's this to do with atheism?

If you're acknowledging that there's a non-contingent first entity then you're not an atheist about a necessary entity. Metaphysical necessity is mutually inclusive with being eternal and omnipotent, so the acknowledgement concedes a lot of important ground to theism.

This is the irresistible force of logic butting its head against the immovable object of reality. Because reality and logic are different worlds, it won't do to just throw words around. They, the words, have to be well-defined so that at least at first they seem to be applicable in both. So your first problem is your words. Your second is your presuppositions: each of your propositions contains at least one that is unclear or questionable. Those being done, then we may look at the argument itself.

Just for example, everything that is in a sequence has a starting point. A circle is a sequence. A circle has no starting point....

Afaik:

There is no first (or last) number on the real number line.

There is no first (or last) point on the circumference of a circle.

There are no edges to the surface of a sphere or an infinite plane.

Also a "necessary being" is a contradiction in terms insofar as for it to be "necessary" means that "being" is unchangeable (i.e. both being and not-being simultaneously). Ergo non-necessary being is necessary (re: PNC) as the entailed negation of the concept of "necessary being".

Lastly, atheism denotes rejection of theism (i.e. theistic conceptions) but not any nontheisms (e.g. animism ... pandeism, acosmism).

It's uncommon to see an argument with multiple premises, all of which are false.

f you're acknowledging that there's a non-contingent first entity then you're not an atheist about a necessary entity. — Hallucinogen

I haven't acknowledged any 'entities', necessary or otherwise. I was going along with your criteria for the sake of argument.
And, afaic, atheism is unbelief in deities, not entities. I'm not an atheist about any specific proposition of your choosing; I'm an atheist by virtue of disbelieving in all deities.

Metaphysical necessity is mutually inclusive with being eternal and omnipotent, so the acknowledgement concedes a lot of important ground to theism. — Hallucinogen

Possibly in some realms of the imagination; not in my reality.

They, the words, have to be well-defined so that at least at first they seem to be applicable in both. So your first problem is your words. — tim wood

Where?

Your second is your presuppositions: each of your propositions contains at least one that is unclear or questionable. — tim wood

Could you explain each?

Just for example, everything that is in a sequence has a starting point. A circle is a sequence. A circle has no starting point.... — tim wood

What defines a circle is the formula for a circle. An observable circle is composed of finite points, but they are all observed simultaneously, they aren't in a sequence in the sense of one point depending on the previous point.

There is no first (or last) number on the real number line. — 180 Proof

They're all contingent on the value of unity, the set as a whole and the series formula. That would be the "first" term.

(i.e. both being and not-being simultaneously) — 180 Proof

Why is this entailed?

Lastly, atheism denotes rejection of theism (i.e. theistic conceptions) — 180 Proof

The point is that denial of a necessary entity entails a contradiction.

It's uncommon to see an argument with multiple premises, all of which are false. — SophistiCat

Do you want to explain why you think this?

I haven't acknowledged any 'entities', necessary or otherwise — Vera Mont

You said

I don't know what the first entity was. I will never know. — Vera Mont

"Was" typically means you're acknowledging it existed.

And, AFIK, atheism is unbelief in deities, not entities. — Vera Mont

A deity fits the definition of an entity.

I'm not an atheist about any specific proposition of your choosing; I'm an atheist by virtue of disbelieving in all deities. — Vera Mont

The deities of monotheism and deism are all metaphysically necessary entities, so disbelief in all deities entails disbelief in those metaphysically necessary entities.

Possibly in some realms of the imagination; not in my reality. — Vera Mont

In objective reality, something that is non-contingent is eternal because it doesn't depend on outside conditions, and it is omnipotent because everything else is contingent on it.
"Your" reality just means your imagination, so it's irrelevant what's true in your reality.

The point is that denial of a necessary entity entails a contradiction. — Hallucinogen

No, the point is that your “contradiction” has nothing to do with atheism. Even if one concedes a necessary entity (note it doesn't have to be an entity at all.) you still have said nothing about a contradiction in atheism.
180 Proof even said it plainly but you still missed the point entirely.
You have to deal with this:

Lastly, atheism denotes rejection of theism (i.e. theistic conceptions) but not any nontheisms (e.g. animism ... pandeism, acosmism). — 180 Proof

Because it renders everything else in your argument powerless.

Ok. We can plod - for a while. What do you mean by "existence" in P1. "Series" is an abstract term; do you mean the Universe is an abstract term? What is a series of events? What is a series of entities?

"Was" typically means you're acknowledging it existed. — Hallucinogen

I was humouring you. But, okay: a first entity existed.
If we take 'entity' to mean any solid identifiable object, that would theoretically have been a sub-microscopic infinitely hot, dense ball of matter that blew itself up. Sounds ridiculous enough on its own, and then you add consciousness and agency and it becomes totally absurd. I could never believe in such a thing.
If we take 'entity' to mean a self-aware organism, there must have been a first one of those, long ago, on some planet of some galaxy. In that case, all of its progeny depended on its having existed, but they don't preclude other organic life arising and becoming self-aware on any number of other planets, in any number of galaxies, and they didn't depend on that one first one, regardless of their chronological order, and none are 'contingent'.

The deities of monotheism and deism are all metaphysically necessary entities, so disbelief in all deities entails disbelief in those metaphysically necessary entities. — Hallucinogen

No imaginary spirits, gods or djinns are necessary. Belief is optional.

(1) Existence is a series of entities and events. — Hallucinogen

That is an assumption - an unsupported supposition.

(4) If all entities are contingent, then there’s no necessary (non-contingent) entity. — Hallucinogen

You seem to be claiming, without stating explicitly or providing support, that existence in a series of events implies contingency, i.e. causation.

The point is that denial of a necessary entity entails a contradiction. — Hallucinogen

– IFF "a necessary entity" is not itself a contradiction in terms, which it is as I've pointed out.

???

Laughable.

Even if one concedes a necessary entity (note it doesn't have to be an entity at all.) you still have said nothing about a contradiction in atheism. — DingoJones

Atheism involves disbelief in, and/or denial of, a necessary being, because metaphysical necessity is a defining feature of an omnipotent, eternal creator.

You have to deal with this:

Lastly, atheism denotes rejection of theism (i.e. theistic conceptions) but not any nontheisms (e.g. animism ... pandeism, acosmism). — 180 Proof
Because it renders everything else in your argument powerless. — DingoJones

And you read my response to it, hopefully? To deny theism is to deny a necessary entity, which entails a contradiction. Rejecting theism but not nontheism doesn't mean not rejecting theism... it's still rejecting theism. Get it?

The point is that denial of a necessary entity entails a contradiction. — Hallucinogen

– IFF "a necessary entity" is not itself a contradiction in terms, which it is as I've pointed out. — 180 Proof

Did you read the earlier part of my response to you? I asked why a necessary being is a contradiction in terms. I'm denying that it entails both being and non-being. That's what I want you to explain.

That is an assumption - an unsupported supposition. — T Clark

No, it's not an assumption. It's a description made possible by distinguishing events and observing entities appear and disappear as conditions change.

You seem to be claiming, without stating explicitly or providing support, that existence in a series of events implies contingency, i.e. causation. — T Clark

Contingency. Contingency isn't the same as causation.

(Aquinas’ ‘five proofs’ and other exercises in scholastic metaphysics were never intended as polemical arguments to persuade unbelievers. They were intellectual exercises given in the context of a culture of belief, intended to provide edification for the faithful. In context where a majority believe that God is dead, these kinds of arguments will only invite hostility.)

Rejecting theism but not nontheism doesn't mean not rejecting theism... it's still rejecting theism. Get it? — Hallucinogen

This is exactly why, as 180 noted twice, you have a problem. Rejecting theism does not entail rejection nontheisms. Therefore, unless you restrict your descriptions to only refer to theistically-derived entities, it doesn't go through at all. Some form of deism, even, could go through.

To deny theism is to deny a necessary entity... — Hallucinogen

For my part, it is merely a matter of being skeptical towards the idea that the theist that I happen to be talking to knows what he is talking about in matters theistic. Is there some reason to think that you are in a position to speak for what all people mean by "deny theism"?

(1) Existence is a series of entities and events.
— Hallucinogen

That is an assumption - an unsupported supposition. — T Clark

No, it's not an assumption. It's a description made possible by distinguishing events and observing entities appear and disappear as conditions change. — Hallucinogen

I believe describing existence as a series of entities and events is inaccurate. That is based on my own observations and my understanding of physics.

Also a "necessary being" is a contradiction in terms insofar as for it to be "necessary" means that "being" is unchangeable (i.e. both being and not-being simultaneously). — 180 Proof

Whatever else is meant by (ontologically) "necessary", this modality also implies unchangeable. The only way X is unchangeable in relation to every other changing Z (i.e. non-necessary Z) is that X itself is simultaneously X & not-X, or always in a state of all of its possible relations/modes; thus, self-contradictory.

I retract my support of 180's post.

Apologies I musta hit a wrong button. I meant to address Hall.

Atheism involves disbelief in, and/or denial of, a necessary being, because metaphysical necessity is a defining feature of an omnipotent, eternal creator. — Hallucinogen

I believe you are mistaken. Atheism involves not believing in or the denial of an omni potent, eternal creator as defined in theism. Atheism is not about a necassary being just becuase that is an attribute of the omnipotent eternal creator (as defined by theism). Just like my poem
about my dog is not a poem about a german shepard even though a german shepard and a husky are both dogs. If I had a husky, or a poem about it.

And you read my response to it, hopefully? To deny theism is to deny a necessary entity, which entails a contradiction. Rejecting theism but not nontheism doesn't mean not rejecting theism... it's still rejecting theism. Get it? — Hallucinogen

Its not though. A necassary entity, on its own, has nothing to do with atheism. Sorry to say sir, but you are trying to use language to smuggle in your argument here. Though often overused I believe the term is “strawmanning”. Your argument is based on a strawman atheism.

(1) Existence is a series of entities and events.
(2) For all series, having no 1st term implies having no nth term.
(3) The universe has an nth term. — Hallucinogen

However, if space and time are in a circular loop, an eternal return, within the wheel of time or a part of the Big Bounce, then no term can be said to be either the 1st or the nth.

In that event, premises 1) and 2) are OK, but premise 3) wouldn't apply.

"B and if not A then not B" does not entail "necessarily A".

B ∧ (¬A → ¬B) ⊭ □A

As an example, a 46th President of the United States requires a 1st President of the United States, but a 1st President of the United States is not necessary.

There's literally nothing in that argument that goes any way towards suggesting that the first "necessary" thing is anything like what we would call a God. Atheists aren't making the claim 'nothing is necessary', they're saying 'these deities in these books don't exist'.

>then you're not an atheist about a necessary entity

And this quote proves what I'm saying - you're confusing 'atheism' about personal gods with some other claim that atheists generally don't make. It seems you've made atheism into something it isn't in order to construct this argument.

It's like saying 'atheism is wrong, because there's fruit. See, look at this fruit. If you believe this fruit exists, then you're not an atheist about fruit". Atheism *isn't about fruit* you goof.