This is a Q & A blog post by our Visiting Scholar in Philosophy, William Lane Craig.
How can I explain the law of infinite regress to my highschool seniors and why it doesn't work?
William Lane Craig’s Response
I take it that your question — Jason — is how you can explain to high school students the impossibility of an infinite regress of causes or explanations.
You can do so by using illustrations to make the point clear.
For example, tell them that an infinite regress is like the fraudulent practice of check kiting. Suppose you have no money in your checking account. But you write a check to someone drawn on that empty account. Then to cover that check you write another check drawn on a different but still empty account. Then to cover that check you write another check drawn on yet another empty account. This could go on forever, and you would never discharge your debts because each check is intrinsically worthless. A first cause is like money in the bank: with it you can produce a real causal effect but without it the proliferation of mere intermediate causes does nothing to effect a real change.
Or think about a train without an engine moving along the tracks merely by having an infinite number of boxcars. Or a watch running without a spring just by having an infinite number of gears. Or a series of skydivers trying to hold each other up even though none of their parachutes opens. Impossible! These illustrations should make it clear why the appeal to an infinite regress explains nothing.