Consider this version of the cosmological argument.
1. A contingent being exists.
2. This contingent being has a cause of its existence.
3. The cause of its existence is something other than itself.
4. What causes this contingent being to exist must be a set that contains either only contingent beings or a set that contains at least one noncontingent (necessary) being.
5. A set that contains only contingent beings cannot cause this contingent being to exist.
6. Therefore, what causes this contingent being must be a set that contains at least one necessary being.
7. Therefore, a necessary being exists.
If you accept this argument, how could the conclusion be falsified