How can Muslims say that God definitely exists?

How can Muslims say that God definitely exists?

The book that Muslims refer to for guidance, the Quran, encourages thought,
reflection and investigation. “Behold! In the creation of the heavens and the earth,
and the alteration of night and day, these are indeed signs for men of
understanding.” (Quran chapter 3, verse 190)
This includes reflecting upon and reasoning whether or not God exists! It prompts us
to study and examine anything and everything in the Universe – from the smallest
sub-atomic particle to solar systems; from the complexity of an insect to the
seemingly mundane such as the clouds and the rain. From reflecting on such things
we can reason that everything in the universe has a cause.
Were this not true, it would mean that the Universe had no beginning, no start point
or point of origin; that it would be infinite. The famous mathematician David Hilbert
stated that “The infinite is nowhere to be found in reality. It neither exists in nature nor
provides a legitimate basis for rational thought.” So, infinity is a theoretical idea that
we cannot sense in the real world. Those who apply it as an attribute of things in the
Universe have departed from reason and are irrational.
Everything we can sense, however different in nature, share certain qualities: they
are limited, finite and dependent on other than themselves. The earth may be very
large, but it still has shape, mass and volume that are of a limited size. The same can
be said of all planets and indeed stars, solar systems and galaxies. All are limited and
all, without exception, are subject to a system of natural laws from which they
cannot escape.
The nature of all these finite and limited things is that they are dependent on other
things. They are neither self-sustaining nor independent. The water cycle is
dependent on the sun, which is dependent on the gravitational laws and the
energy produced by nuclear fusion, and so on. Men – and all creatures - have
needs that require satisfaction in order to survive. Nothing is self-subsistent. So things
exist, but do not have the power of self-existence, nor can they control when they
die, change to become something else, or cease to exist.
If everything in the Universe, which is made up of lots of limited parts, has a start
point and is dependent upon other things, then what is everything dependent upon
for its existence? The proposed “Big Bang” would have been preceded by
something. What is that something? Another universe? If so, then what was before
that? The chain would continue until a true “beginning” was found.
So the beginning could only be caused by something else - a creator. But, if that
creator shared the same properties as the Universe - being limited and dependent -
then that creator would also require a creator, as this is the case with every limited
thing. So the Creator, which originated everything, must be different - uncaused or
eternal, unlimited and independent. This Creator is what we call God, or Allah.