Sibling rivalry and the beginning of time

Greg Koukl has this tactic he calls "sibling rivalry." That's when somebody raises two objections, often unrelated to each other, but these objections are inconsistent with each other. The tactic is just to point it out. You say something like, "When you were objecting to this thing, you said P, but now that you're objecting to this other thing, you say not-P. Which is it?"

I wanted to mention one example of this I was just thinking about today. There are two philosophical arguments for why time had to have had a beginning. There are more than two, of course, but there's just two I want to talk about right now. One of them is the argument from the impossibility of an actual infinite. The other is from the Grim Reaper Paradox.

In response to the argument from the impossibility of an actual infinite, people will sometimes point out that a line of any finite length can be divided infinitely, or they point out that a line of any finite length is made up of an infinite number of points.

In response to the Grim Reaper Paradox, people will point out that once you reach the Planck time, you cannot divide time any further, so you cannot fit an infinite number of Grim Reapers into a finite interval of time.

These objections are at odds with each other. If Planck time was all that prevented us from carrying out a thought experiment involving Grim Reapers, then surely Planck length would just as well prevent us from carrying out a thought experiment involving the division of some length. But if Planck length is irrelevant to the thought experiment involving the division of some finite length, then Planck time is irrelevant to the thought experiment involving Grim Reapers.

So one of these objections fails no matter how you look at it. That means at least one of these arguments for the beginning of time survives the objections.

Arguments from incoherence

There's a whole family of arguments against God's existence that try to show that there is an incoherence in the omni attributes of God. They all take basically the same form. They ask if God could do something and argue that if he can, then it violates one of his other attributes, or if he can't, then it violates his omnipotence. So either way, a God with all these omni's can't exist.

Here's a few examples:

If God exists, then he is both all powerful and perfectly good.
If God is capable of doing evil, then he is not perfectly good.
If God is not capable of doing evil, then he is not all powerful.
Therefore, God does not exist.

If God exists, then he is all powerful.
If God can create a rock so heavy that he can’t lift it, then he is not all powerful.
If God cannot create a rock so heavy that he can’t lift it, then he is not all powerful.
Therefore, God does not exist.

If God exists, then he is all knowing and all powerful.
If God can change his mind, then he is not all knowing.
If God cannot change his mind, then he is not all powerful.
Therefore, God does not exist.

If God exists, then he knows everything and can do everything.
If God can create information that he doesn’t know, then he is not all knowing.
If God cannot create information that he doesn’t know, then he is not all powerful.
Therefore, God does not exist.

I decided to write on these today because that last one has come up twice just in the last two days in my on line discussions which makes me wonder if there's a meme floating around out there, or some popular atheist out there said something that's gone viral or something. Anyway, I thought I'd address it.

All of these types of arguments are trivially easy to answer. The usual way of answering them is by pointing out that they all assume an incorrect definition of omnipotence, then correcting the definition. Sometimes this results in an argument over what the real meaning of omnipotence is. But it doesn't matter. All of these arguments fail no matter what definition of omnipotence you use. Here are the competing definitions of God's omnipotence:

1. God can do all things logically possible.
2. God can do anything whatsoever, including violate the laws of logic.

If (1) is true, then all the arguments fail because each of these arguments is asking whether God could actualize a logical contradictory state of affairs. A state of affairs in which God is omniscient but doesn't know everything is a contradiction, so God can't create information that an all knowing God doesn't know. A state of affairs in which God can do anything but can't lift a rock is a contradiction, so God can't create a rock that an all powerful God can't lift. If omnipotence doesn't include the ability to do logically impossible things, then God's inability to do these things doesn't count against his omnipotence.

If (2) is true, then all the arguments fail because because they remove any basis for saying there's anything God can't do. God could create a rock he can't lift and still be able to lift it. He could be all powerful even if he's not all powerful. He could create information he doesn't know and still know it. He could be all knowing even if he's not all knowing. He can be perfectly good even if he's evil. He can change his mind even if he doesn't change his mind. There is no state of affairs he couldn't actualize and still be omniscient, omnipotent, and wholly good.

So regardless of how you define omnipotence, these kinds of arguments from incoherence always fail.