Can God Change the Past?

Can God change the past?

No . . . and this question is a real doozy! (But a doozy that brings with it important clarifications of the nature of God’s power.)

If you enjoy science fiction, you’ve undoubtedly encountered stories of time travel, like H.G. Wells’s The Time Machine. One common theme in these stories is to travel back in time to prevent some horrible event (like Hitler’s rise to power). To make up a quick example, perhaps a time traveler eats a rabbit, unwittingly depriving a starving woman in the woods of food. She dies . . . and now doesn’t go on to give birth to the man who was supposed to give the world some great medical discovery.

I imagine that most people would agree that we cannot travel backward in time to change things that have already happened (at least not yet!) . . . but is it truly even possible for us, or even for God almighty?

In Thomas Aquinas’s day, some held that God could go back in time to make events that happened not to have happened, not fully grasping the distinction between possible and impossible things. Thomas shares this profound quotation from Augustine, to the contrary:

“whoever says, if God is almighty, let him make what is done as if it were not done, does not see that this is to say, if God is almighty, let him effect that what is true, by the very fact that it is true, be false.”

Most intriguingly, Thomas also shares this insight from the pagan Aristotle:

“of this one thing is God alone deprived—namely, to make undone the things that have been done.”

Thomas himself says, “There does not fall under the scope of God’s omnipotence anything that implies a contradiction.” God is able to do all things that are non-contradictory—that is, all things that could possibly be done. Regarding all things possible, there are no limits to his power. He can raise the dead and create the entire universe ex nihilo (“out of nothing.”) But because he is truth, he cannot make an event that truly happened not to have happened, which would make what was true false.

Thomas also shares an insight of great relevance to every one of us as sinners. Though even God himself cannot make it so that we had never sinned in the past, he can remove every corruption or stain of sin within our bodies and souls (recalling his limitless power of “sparing and mercy”).

Did you enjoy this excerpt? There is so much more to learn!

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