We no because there are seasons on earth were things die and things come into life. People die and come into live.
Look at the day and the night, look at the childhood which follows adulthood. Everything moves from one stage to the other and the universe has an age, right?
So we have established that there are contingent beings or lifeforms that are being brought into existance and brought out. So then you must conclude that someone or something that is incontingent that is bringing things into life and then taking them out.
That is God/Allah to me and that is a proof. The universe is contingient on God as is everything else.
