How Could The Universe Be Eternal

Imagine you’re standing in a huge manufacturing facility. This factory makes underwear. The fact that it makes underwear is not important to the story, I just think it’s funny. So you are standing next to the assembly line. You watch all the whitey-tightys zipping by. You look to your left and realize that the factory is so big, the assembly line disappears in the distance. As you are admiring the size of the factory, a worker comes over. She comments, “there’s no start to the assembly line.” You disagree and ask where all the underwear are coming from. She responds, “oh, these are self-existing underwear. They have no beginning.” Although you can’t see the other end of the facility, you know she has to be wrong. You ask her how she knows they are self-existing, eternally old underwear and she says, “oh because I work here.” 
What caused that beginning? Oxford’s Anthony Kenny once said, “A proponent of the Big Bang theory, at least if he is an atheist, must believe that … the universe came from nothing and by nothing.”⁠1 For the secular humanist, and general atheists as well, nature must be self-existing and continuous. This is because their worldview excludes anything but naturalism. It is absurdity to claim that a currently self-existing universe sprang into existence from nothing and by nothing. 
In a similar way the secular humanist is hard pressed to give a satisfying alternative explanation of how the universe exists but never began. It’s like saying, “I flew from Dallas to New York yesterday, but the flight never started.” It is a nonsense statement with first order absurdity. It’s for this reason that atheist and the Secular Humanist is in a difficult spot.
To continue to assert the untestable dogma of an eternal universe is to deny modern science. To accept a universe with finite age is to deny Secular Humanism’s fundamental claims of self-existing nature, and continuous process. Although these idea are guarded vigorously, there is no satisfactory evidence for their claims. These ideas are philosophically unproductive, and there is nothing but absurdity in their adherence. 
The only logical conclusion is that nature is contingent. Reason compels us to recognize the necessity for causality. To claim that the universe is self-existing, and that man is a result of a process without end or beginning with no causal event begs the secular humanist to abandon everything that is known empirically and theoretically. There is nothing gained, nothing pragmatic, nothing methodologically useful, in accepting a self-existent universe.

1 Anthony Kenny, The Five Ways: St. Thomas Aquinas’ Proofs of God’s Existence (New York: Schocken Books, 1969), p. 66.