During a brief encounter with Naureen (a theist of unspecified species), I was asked the following two questions:
1. Name something that does not exist and its attributes don't exist in our reality; and
2. Name something in our human experience that ever came out of nothing.
I'll address these questions now and wait for Naureen to respond via comments.
1. Name something that does not exist and its attributes don't exist in our reality
I. What I exclude
a) Logical impossibilities
There are some things that (subject to assuming that logic is universal) I can say don't exist in our reality because they are logically impossible.
A square circle - in other words, an object which is a square and a circle at the same time. This object is logically impossible. the attributes of a square are such that they exclude the attributes of a circle. A thing can't be a square and a circle at the same time because it would breach the First Principles of Logic. In other words, it would be something while being something that it's not (the Law of No Contradiction). This is because a circle does not, by definition (it can't), have any straight lines. A square, on the other hand, has four straight lines that it uses for its sides. A square circle is a circle that's not a circle. It's a logical contradition. It can't exist in our reality or in any other reality in which logic applies.
I would agree with Narueen (we've had some twitter discussions after she posed the question) that the concept of a square circle can exist in our reality. While we can't conceive of the actual object, we can (if we really stretch it) imagine that there may exist some reality in which logic does not apply and in which an object that is both a square and a circle is possible. The concept then (although impossible for us to imagine) exists in our reality.
Some versions of gods are similar to a square circle. They are logically impossible. For example a truly (absolutely) omnipotent God is a logical contradiction: the good old stone paradox (can God create a stone that's so heavy that He is unable to lift it?) Of course, this is a sideline comment and I don't intend to go into a lengthy debate about this paradox (I've seen, and discussed at length, various proposed solutions).
Is it possible that, in our reality, there exist objects that logic doesn't apply to? Perhaps. I can't prove that logic is universal, even within our reality. Perhaps they are and we can't perceive them because they contradict our way of seeing the world. Perhaps some things that we see as circles are actually square circles? I can't say for sure. But assuming that logic is indeed universal within our reality, a square circle is my answer.
b) Empirically exluded things - theistic God
Another example, and closer to the topic of the discussion, of a thing that doesn't exist in our reality is a theistic God. In this case, I define theistic God as a god who intervenes in human affairs.
I can say that such a god almost certainly doesn't exist. We have solid experience of human affairs and we know from this experience that there's no evidence of the existence of a god who intervenes in human affairs. Everything that happens in our world, everything that we observe, appears to act according to laws that we call "laws of nature". There are no documented (ie, observed and established to exist, beyond fraud or hallucination) instances of things breaching laws of nature. There are, of course, some things we don't fully understand. One of these is ball lightening. But lack of understanding of a phenomenon doesn't entitle us to assume that it breaches the laws of nature.
What type of events would class as breaching laws of nature? For example a man who lost a limb, prayed, and the limb just suddenly reappeared. Or an car that's about to crash into another car but inexplicably is raised into the air, suspended in the air until the other car passes by, and then gently put on the ground.
Things like these do not happen. Instead, what we observe is that everything around us is acting consistently in accordance with natural laws. What we observe, in other words, is exactly what we would expect to observe if there was no God who intervenes in human affairs.
Insofar as this type of god goes, I'm a strong atheist. I deny (with almost complete certainty) that such a god exists.
That's not to say that I'm dogmatic about this. If someone presents me with credible evidence (or argument) that such a god exists, I'll accept that and become a theist.
II. What I don't exclude
What I don't (and can't) exclude, however, is the existence of some intelligent entity who created the Universe and went into hiding (or disappeared or just takes no active role in the Universe, or at least in human affairs).
While I can't exclude that such a god may exist, I don't start from an assumption that such a god does exist. Quite simply, there's no evidence (not even a sound philosophical or logical argument) that would allow me to conclude that such a god exists.
Insofar, as this type of god goes, I'm a strong agnostic atheist. I don't exclude that such a god may exist but I believe that this type of god is very unlikely to exist. That's because the more conditions a proposition contains, the more unlikely it is to be true. You can see me demonstrate it mathematically HERE.
That's not to say that I'm dogmatic about this. Not at all.
If someone successfully rebuts my mathematical proof, I'll be a weak agnostic atheist about this type of god (I'll simply lack belief, without saying that this god is very improbable).
Furthermore, if someone provides me with credible evidence that such a god exists, I'll accept that and become a deist. So far, no good.
2. Name something in our human experience that ever came out of nothing.
I now turn to the second question.
I don't know of anything that humans have experienced (or, in other words, observed) and which comes out of nothing. And yet, I don't propose that anything did come from nothing.
Insofar as I'm concerned, it's theists who propose that their chosen god (be it Yhwh, Allah, or the Flying Spaghetti Monster) created all matter out of nothing. In my books, it's them that Naureen should be asking this question. As an atheist, I make an honest statement: I don't know where the Universe came from, I'm excited about the question, I think it's a fascinating topic to ponder and I think we should keep looking for the answer (which, coincidentally, we may never actually be able to find).
Theists claim to have some knowledge about matters that they have had absolutely no experience of (nobody has experienced/observed something being created of out of nothing, Naureen, even with the agency of an entity such as a god) while atheists don't.
There are some atheists, in particular some physicists (such as Krauss) who propose that the Universe came from nothing. But what they're proposing is just a hypothesis. They're not claiming that their model is verified by any observation. I have no problems with that. Equally, I have no problems with someone proposing a god (except for a theistic god; see above) who created the Universe out of nothing. I'm fine with that, so long as the proponent makes it clear that they're merely putting forward a hypothesis, that they have no evidence to support it and that they're not claiming that this is what in fact happened.
And again, as above, if I'm presented with solid evidence or a sound argument that such a god exists, I'll accept it and become a deist.
I can also add (as I've indicated on twitter during my brief exchange with Naureen) that the question is unusal for this topic. Naureen asks me to demonstrate something in our human experience that comes from nothing. But we both know (well, I know, and I hope she does too) that the generation of our Universe is very much unlike anything that we've ever experienced/observed. No matter how the Universe came to exist, that event will necessarily be something that's completely inconsistent with anything we've experienced/observed. If an invisible and powerful God created our Universe from nothing, it will be something completely out of the ordinary for us (no human has experienced or observed this type of event). If another form of matter/energy changed into our Universe, that will also be something that we've never experienced/observed. And finally, if the Universe (without a god) came from nothing, we also have no experience/observation of things like that happening.
Creations of Universes are not things that we have experience of. They are necessarily things very much beyond the scope of our experience and, one way or another (no matter how they happen), they will involve things that we've never observed.
I hope that answers Naureen's questions. I tried my best.
Comments are welcome