1.) God is perfect.
2.) If God is perfect, then God would create the greatest possible world.
3.) The possible world where evolution and an old earth are the case is greater than the possible world where Young Earth Creationism (YEC) is the case.
4.) If YEC is the case in this world, then this is not the greatest possible world.
5.) If this is not the greatest possible world, then God is not perfect.
6.) If YEC is the case in this world, then God is not perfect.
Conclusion: YEC is not the case.
There are several background premises which must be established in order to convince anyone to accept this argument:
A.) We must accept Leibneiz’s idea that there could be a best possible world.
B.) Possible worlds must be set by what God can imagine.
C.) If we can imagine a world where old earth and evolution are the case, then surely God can as well. Therefore, a world where old earth and evolution are the case is a possible world.
D.) We must accept that the YEC story is pretty lame compare to the modern scientific view. I have no objective standard for which world is greater. Premise (3) largely depends on subjective assessment of the two worldviews. Old earth and evolution seems almost infinitely more fascinating to me than YECism. Knowing the size and age of the universe creates an even greater sense of the power and glory of God. Evolution creates a greater sense of the creativity and patience of God. If YEC were true, anyone who has studied modern Physics or modern Evolutionary theory would have to wonder how humans could have invented things that are so much more interesting than what God actually did. They might even conclude that they could have done a better job designing the universe than God.
E.) We must accept that in order to be perfect God must create the best possible world, but I don’t think that should be too controversial if we have already accepted Leibniz’s view that there is such a thing as a best possible world.
F.) If A-E are accepted , then the rest of the work is done by simple logic.
 Plantinga has argued against Leibniz’s view in The Nature of Necessity. (Very unconvincingly in my opinion).
- Ken Ham, Young Earth Creationism, Young People Abandoning Their Faith: My Daughter’s Story (spiritualsoundingboard.com)
- Should YECs do a Phd? (justificationbyreason.wordpress.com)
- PCA 2013 General Assembly – The YECs get their turn (geochristian.wordpress.com)
- Forbes Supports Kent Hovind? (sensuouscurmudgeon.wordpress.com)
- The New York Times hosts a superfluous debate on evolution vs. creationism, including more dumb accusations that science is based on faith (whyevolutionistrue.wordpress.com)