https://physics.stackexchange.com/a/340552:
Science doesn't tell us the reason things happen. It provides a way to develop models which predict what will happen. For all we know, Zeus himself personally causes every radioactive atom to decay when he sees fit. Science cannot disprove such a claim.
What we can do is use the scientific method. In the scientific method, we pick a "null hypothesis" which is what everybody expects to happen, and an "alternate hypothesis" which is the interesting thing we want to test. Then we run an experiment and hopefully show that the null hypothesis is highly unlikely, while our alternate hypothesis is good. In the case of this topic, the usual null hypothesis is "radioactive decay is random."
To date, nobody has been able to develop a test which can demonstrate that they can predict the timing of radioactive decays better than random chance. That's not to say there's not some local hidden variable, or a cherub that knocks the atom about to cause it to decay. It just says that nobody has been able to provide such a theory which does better than the "radioactive decay is truly random" theory does.
So, there may be a perfectly non random reason, but if so, that reason is similarly random. For example, if one hypothesizes a particle that ‘hits’ atoms that causes them to decay, those particles must hit atoms with a particular random distribution to explain the data we see.
And yes, t radio-active decay could be driven by a 100% predictable random number generator, but if so, we haven’t noticed yet, so that random number generator must be very, very good.
https://www.scientificamerican.com/article/new-views-of-quan...
'In common parlance, randomness is the apparent lack of pattern or predictability in events' [1].
It doesn't mean there is no cause, but we can't predict the outcome of the random process [2].
In some case we can't predict it because we don't understand it, in others it is inherently unpredictable according to our model of the world.
As for radioactive decay, specifically: 'According to quantum theory, it is impossible to predict when a particular atom will decay, regardless of how long the atom has existed'[3].
That only means quantum theory can't predict it, it doesn't mean other theory won't be able to.
It's just we're stuck with quantum theory for now, because it has been verified by all experiments done so far, and not yet disproven by new experiments.
Every theory has a lifetime as long as it is not proven wrong by experiment. And cause and predictive capability are directly tied to particular theory/model you're using.
so 'random' might mean:
1) we have a good coherent model, consistent with empirical results, and a particular process/phenomenon is unpredictable according to our model.
or alternatively
2) we don't have a good model/don't understand the cause and therefore can't predict the outcome a particular process/phenomenon
both 1 and 2 leave space for a new theory to come in, and be able to explain the cause/make the prediction and eliminate 'randomness'
so essentially you're right.
[1] https://en.wikipedia.org/wiki/Randomness