In classical apologetics two major arguments for the existence of God are based upon observations of the natural world. The teleological argument argues that the evidence of design in the world is evidence of a God who created it all. The cosmological argument argues that because the universe exists it must have a beginning and a Being who brought it into existence.
The longer form of the cosmological argument begins with the statement that the physical universe exists. Everything that exists in the physical realm must have a cause. The cause cannot be the universe itself. The cause must exist outside the universe and have the ability to bring the universe into existence. The cause that brought the universe into existence is God. Because the universe exists, God exists.
This argument finds support in the observations of science. No natural mechanism is known by which something can arise from nothing. The normal arrangement of the world shows the things that exist in the physical world have their source in things with an earlier existence. Everything we observe is contingent upon an ancestor or a creator. The first law of thermodynamics seems to support this argument with its declaration that energy cannot be created or destroyed. Since the physical universe exists and it could not have risen from nothing it must have a source great enough to bring the universe into existence.
Like other arguments from classical apologetics the cosmological argument is primarily a philosophical argument. The proofs offered by this argument are not based upon physical evidences for an act of creation, but upon the logical necessity of a causative agent bringing the universe into existence. This argument is easier to understand and explain than the ontological argument because it is based upon premises which are more familiar to the average person. This line of reasoning may be reflected in Psalm 19, “The heavens declare the glory of God and the firmament sheweth His handywork.” All creation speaks to the necessity of a Creator. Because this universe exists there must be One who brought it into existence. To know the nature of this Creator a person must turn to the Bible. Genesis 1:1 simply states, “In the beginning God created the heaven and the earth.” The reality of God can be glimpsed in creation, but the character of God is only found in the Bible. He has revealed Himself clearly through His Word. God’s command to all men is to believe His Word.