On the contrary, The Apostle says: The invisible things of Him are clearly seen, being understood by the things that are made (Rom. 1:20). But this would not be unless the existence of God could be demonstrated through the things that are made; for the first thing we must know of anything is, whether it exists.
I answer that, Demonstration can be made in two ways: One is through the cause, and is called a priori, and this is to argue from what is prior absolutely. The other is through the effect, and is called a demonstration a posteriori; this is to argue from what is prior relatively only to us. When an effect is better known to us than its cause, from the effect we proceed to the knowledge of the cause. And from every effect the existence of its proper cause can be demonstrated, so long as its effects are better known to us; because since every effect depends upon its cause, if the effect exists, the cause must pre-exist. Hence the existence of God, in so far as it is not self-evident to us, can be demonstrated from those of His effects which are known to us.

Thomas Aquinas. (n.d.). Summa theologica. (Fathers of the English Dominican Province, Trans.). London: Burns Oates & Washbourne.