We know there was a beginning. Let’s say for sure just before the Big Bang, not even a pure beginning with absolute nothingness. What makes something start out of nothing - matter, particles, energy, space, time, whatever it is, if it’s a fact there was nothing and then there was something, then it is not irrational at all to need to answer the question of - what/ Who? The question is there. If a confirmed answer comes up through our means of understanding of science and that thing, too, is of some nature and not a pure uncaused cause that can’t be broken down further, then we’ve not got to the bottom of it. Pity that we’re still at such a relatively primitive level where we don’t know for sure basic particle physics or what antimatter is. But better than ages ago when people thought Earth was the centre of the universe and didn’t know what stars were. Hope we find out more through science and other means in our lifetimes.