When the word" exist "occurs like "numbers exist "does it mean what it means in sentences like "Dogs exist"?

I am wondering if there is an alternative between nominalism and realism. Both of these theories agree that particulars exist but they disagree about the relationship between the particulars and their properties. However, what if there are no individual particular entities that are independent with their own self-nature? In our modern times, we often discuss how entities are interconnected and, to some extent, dependent on other entities. In the field of Social Work, for example, the micro, mezzo, and macro environments affect each other and the line between the three are constantly blurred and uncertain. Believing in a "mechanical" world that is made up of separate individual parts is becoming increasingly difficult to believe.

We all know beyond the universe, there's nothing. How come is that possible? Theory says the big bang happened, and that theory has been accepted since it was "released". But where was the energy that caused it? And how did it existed, if there was nothing? Is there anything in the "nothing"? And, if we talk about religion, how did god exist? Who made it? How was he created if there was nothing? Some people say it created himself, but how the heck that happened if there was nothing?

The Kalam Cosmological Argument has as its first premise "Everything that begins to exist has a cause" (at least in the form I've heard it). Often examples of "chairs" or "people" are given for things that began to exist. But this seems to be a category error - the Universe did not begin to exist in the same way that a chair does. Indeed a chair doesn't "begin to exist" in that it was created from other things. So to me it sounds like the argument overstates its case with "everything that begins to exist" since the only thing that has begun to exist is, well, everything. One could restate this premise as "The universe began to exist" could it not? Is I missing something or is this what is meant by this argument? If so it seems to be more of an assumption than the inductive reasoning I hear it being used as (e.g. "you've never seen a chair 'pop into existence' have you?").

If something can’t be defined can it exist? and vice versa

Is there a clear way to distinguish physical and non physical things? I'm not implying that there are non physical things. I would prefer if you didn't define "physical" as whatever is studied by physicists.

Do rainbows exist? I assume rain drops and sunlight exist, but the rainbow is not a collection of rain drops, nor a region of the atmosphere where passing rain drops get some colour, is it? Should we say that rainbows are optical illusions? Or what?

There are many fascinating views regarding material constitution. It seems to me that a car, for example, could not be one or several parts, all of its parts laid out in front of you, all of its parts put together, or enough parts put together in such a way that it allow the object to carry out its primary function (transportation). Therefore, it seems to me that a car is merely a fiction or perhaps it is better to say that the car has no independent "essence" that is separate from the parts. I often wonder if human beings are in the same situation as cars. Is it possible that we are also fictions like cars? This seems difficult to believe because we normally view ourselves as being persistent entities that remain the same. Our bodies certainly change and we might grow (or diminish) in intelligence but we still view ourselves as being the same individual. Thanks

If every thing has being then how can non-being, as a concept, not have being? Wouldn't it have being by virtue of its distinction from being? I.e. in being 'non-being'- it 'is' that which is 'not being' (the conceptual complement of being) and as it 'is' non-being - distinct from being, it is 'being' no? And so if this is the case, and being is thus a characteristic of all things - then what of being itself?

Can philosophy speculate as to the likelihood of their being aliens on other planets or intelligent life elsewhere? If so, what do philosophers have to say about this and what do you philosophers on this forum have to say?