How can God create something (the universe) from nothing (before the universe there was nothing)? That’s a logical contradiction, isn’t it?

I don’t see the connection between what you asked here and the talk about being His own cause, etc., in the opening message.

In any case, regarding your question here, I don’t see this as a logical contradiction. At most it is a physical impossibility (like performing a miracle against the laws of nature and beyond natural human abilities).
True, Nachmanides, in the commentary attributed to him on Song of Songs (vol. 2 in Chavel), does see this as a logical problem, and therefore makes a Platonic claim that there was a primordial hylomorphic matter (based on the well-known midrash from Pirkei de-Rabbi Eliezer: “From what were the heavens created? From the snow beneath His glorious throne…” — which Maimonides in the Guide describes as the most astonishing midrash he had ever seen). But in Genesis he contradicts those statements of his (and I suggested a resolution in my article on Torah and science). In any case, for my own part, I disagree.

What I meant in the opening is that if God can create something from nothing, then why not assume that the world itself was created from absolute nothingness, even without God?

Why isn’t that a logical contradiction? How can something be created from absence? You can’t “quarry” anything out of nothing.

What does “you can’t” mean? Can’t, like you can’t fly in the air, or can’t, like making a square circle? The first is a physical inability and the second is a logical one. The second is a logical contradiction because a triangle is not a circle and vice versa. But creation ex nihilo, at most, contradicts the laws of nature; it contains no internal logical contradiction. It’s not that there is both nothing and something at the same moment. That would be a logical contradiction. There was nothing, and now something exists. There is nothing contradictory here. At most, a human being or some other creature can’t do it. So in my view it is not essentially different from the splitting of the sea or “sun, stand still at Gibeon.”

It’s like a square circle. How can nothing be turned into something? That is a logical contradiction exactly like a triangle that is circular.

And if indeed something can come into being from absolute nothingness, then there’s no need to assume there is a God.
Maybe one day the void woke up in the morning and decided that suddenly a world would come out of it.
P.S. I remembered that certain interpretations of quantum theory allow this, and as I recall the late Stephen wrote this too: that the energies cancel each other out and thus you get a free lunch. Like a mountain and a pit.

I can’t keep repeating the same thing again and again. I explained it. If you don’t agree — your health.

Maybe explain it one more time? After all, first there is nothing and afterward something is created. And from nothing, logically, something cannot be created, because there is nothing in it at all. That is why it is called “nothing.”

And you didn’t answer why you don’t accept actual creation of something from nothing — I mean even without God. According to your approach, is that a logical contradiction or not?

I think the fact that something cannot come into being from nothing is physical, not logical (the concept of “nothing” does not mean “there is nothing and there never will be anything,” but simply “there is nothing” — therefore the fact that afterward there is something is not a logical contradiction).

And that also answers the second question — physically it can’t happen, and this is where God comes in: He can break physical laws.

I have nothing to explain here. Can you explain why clouds are not kindhearted and why their hands are not longer than their ears? The premise of your question is absurd on its face, and you yourself even write this, since you yourself brought up that in quantum theory they speak about something arising from nothing, and at the same time you continued to argue that this is a logical contradiction. A thing and its opposite. So what exactly do you want me to answer?
As A.H. explained, exactly what I wrote to you above: this is a physical problem, not a logical one, and therefore a human being cannot do it and God can. That’s all. I have nothing more to say.