In a possible reality, if something came into existence without something giving rise to it, the fact would be that , there was nothing stopping something from coming into existence without anything giving rise to it, and if this was the existing fact, this is the thing that gave rise to it, in a possible reality, is that fact, the objection I heard is this : but the thing already happened without a cause, so how does this argument make sense, but explain how this makes sense as an objection as if this was a possible reality this would HAVE to be the case, thus showing that it doesn't work in a possible reality.
At the quantum level, particles can come into existence spontaneously, without a definite cause.
If the universe could arise this way, without a direct preceding cause, the laws of quantum mechanics would still provide the mechanism for how this occurs. The quantum vacuum is not pure nothingness, but a state with physical laws that allow uncaused emergence.
So while there was no first cause before the universe, the laws of physics themselves allow, and give a logical basis, for how the universe could spontaneously arise. The laws explain how something can come from nothing - not temporally before, but by describing the process of uncaused emergence.
You can watch this - https://www.youtube.com/watch?v=46sKeycH3bE
Lawrence Krauss: A Universe from Nothing
We do sometimes speak of negative causation, where an absence is interpreted as functionally covariant with an event (i.e. the null input into some causal function yet has a nonzero output). So we might say:
- Uncaused object X "popped into existence."
- Nothing was preventing X from popping into existence.
- If nothing prevents some a from popping into existence, then a will pop into existence.
- So X's existence is caused after all. But this contradicts the definition of X.
Is this a real contradiction? (3) is a conditional ranging over whichever a we have in mind, and is an existential conditional, no less. So it has the veneer of a statement of a causal relationship. However, there are two moves we can make: redefine X as having no positive, substantial cause, or distinguish first-order from second-order causation. These moves are probably equivalent when specified enough: causation-by-absence would itself be second-order, then, and (3) can be true of X such that when we say, "X is uncaused," we mean that it has no first-order cause, whereas when we say, "X was caused by the absence of an anticause," we mean it has a second-order cause.E
EThat is, we can ask, "What is the cause of X not having a cause?" but then we need to reframe that as, "What is the cause2 of X not having a cause1?" where the subscripts mark out the difference in order/type.
The question "Must everything have a cause?" is a metaphysical question. Therefore, no appeal to the body of physics directly can solve the question, because the question is one of metaphysical grounding (SEP). From the SEP:
The point of departure for theorizing about grounding is that there are a variety of claims—claims we make in ordinary life as well as ones we make in the context of doing philosophy—that are best interpreted as being claims about what grounds what. As for metaphysics in particular, some claim that grounding plays a central role in the enterprise properly conceived. Schaffer, for example, writes that “metaphysics as I understand it is about what grounds what” rather than what exists (2009: 379)
Thus, it depends on your metaphysics, to an extent, of what answer you might accept. But let me suggest a path in line with conceptualism. From WP:
In metaphysics, conceptualism is a theory that explains universality of particulars as conceptualized frameworks situated within the thinking mind.2 Intermediate between nominalism and realism, the conceptualist view approaches the metaphysical concept of universals from a perspective that denies their presence in particulars outside the mind's perception of them.
Cause is a concept that is used by the mind in the conceptual reality it constructs. When I turn on the light with a switch, does my finger cause the light to go on or my brain? Do the molecules in the switch play a role in the cause? What about electricity? What about Thomas Alva Edison? Did he play a role in causing the light to come on? What about the James Clark Maxwell? What about J.J. Thomson? We see the problem of proximate, distal, and ultimate causation reveals something about the nature of causation itself.
So, from the perspective of a conceptualist, a cause isn't even real, and the experience and determination of cause are highly teleological in nature, and if that's the case, who's to say that everything must have a cause, and that such an attitude is not just peculiar for the demand for logical consequence to be a cognitive tool wielded to explain everything. Perhaps everything need not be explained. Is being random not the inability to determine a cause, and should we view stochastic processes in the universe as causal? In this sense perhaps anything beyond our physical capacity to compute cause has no cause. This would echo some religious views. Many religions, for instance, will tell you that somethings are beyond explanation and understanding.
Your question is an excellent question, because it admits a lifetime of study and challenge. As such, there is no short, canonical answer to it. For more information, read up on the Principle of Sufficient Reason.
A partial answer / framing challenge.
It may be more helpful to think of necessary antecedent states than causes.
Empirically, we can't actually measure causation X -> Y, we can just measure that every time we've been able to measure a state of character Y and the state right before it, the state right before it has character X. "X causes Y" is a model, not a measurement. The question linked in the comments and CriglCragl's answer to it may be of use.
And in the physics of the very small, the following events keeps repeating themselves - theorists predict a certain kind of hitherto unidentified particle or interaction is not prohibited by the laws of physics. Experimentalists go looking for that kind of particle or interaction where the theorists say it is possible. It turns out to be real. "That which isn't prohibited is mandatory" seems to be a pretty effective rule of thumb - but "isn't prohibited" includes a description of the antecedent state (to satisfy conservation laws).
This question pops up a lot. Philosophers have been pointing out for centuries that this breaks down when we try to extend it beyond tangible objects in our universe. For example, the existence of Time could not have had a cause in Time. Or if we mean that everything must have a logical reason for existing, logic must start from axioms, which are unprovable.
In a universe without cause and effect, anything could occur anywhere at any time. For example, philosophers and other large objects would pop into existence for no discernable reason, only to disappear moments later in a puff of Fitch symbology... Conversely, in that universe, causes which we would expect to give rise to effects would not. These things make it highly unlikely if not impossible for life or philosophers to arise and persist in such a place.
Some events in physics are random: they may happen within the given time, they may not. Like, during radioactive decay, the atom nucleus may split within the next hour, or it may not. This cannot be predicted for the single atom. Even more, this fundamentally cannot be predicted.
Hence I think there is no reason for the particular atom nucleus to split in the next hour, while it still may. If it does split, this is likely event without the reason.
Of course, with the bigger chunk of radioactive material, statistical averaging means that certain quite predictable percent of nucleus will split. But it is possible to design the experiment where individual reactions are counted, observing this randomness.
There is even hypothesis that all known fundamental laws of physics are just statistical.