What is the nature of time?
Three views have been proposed:
- Presentism holds that only the present is real (so the past and future are not)
- The growing block theory holds that the past and the present are real (but the future is not)
- Eternalism holds that the past, the present, and the future are all real
The Church does not have an official teaching on this, and orthodox Catholics take different views.
However, the Church does teach (as we recently saw) that God is eternal—outside of time—and this seems to have implications for the nature of time.
Let’s suppose that presentism is true and that only the present exists.
What would that mean for God’s eternity?
The Eternal Now and Presentism
In this case, we could speak of two moments that are actually real:
- Outside of time, there is God’s “eternal now”
- Inside of time, there is the present, which we may think of as the “temporal now”
The former is, by definition, changeless, while the latter changes constantly.
At one moment in the temporal now, it’s 8:00 a.m., but a minute later it’s 8:01 a.m., and so forth. At one moment, you’re waking up, at another moment you’re getting out of bed, etc.
How would an eternal, changeless God relate to a constantly changing temporal now, if that is the only moment of time that exists?
Here we run into what strike me as problems. We’ll look at several of them.
Getting the Universe Started
If presentism is true then, in the eternal now, God would create time—a single moment (the “temporal now”) which constantly changes, alongside his changelessness.
One of the things that is constantly changing about time is what the current time actually is. Suppose that God created the universe at 12:01 a.m. In that case:
- At the moment of creation, the temporal now is 12:01 a.m.
- One minute after creation, the temporal now is 12:02 a.m.
- Two minutes after creation, the temporal now is 12:03 a.m.
- And so on.
It follows that God knows all of these things in the eternal now. Thus:
- In the eternal now, God knows that at the first moment of creation it is 12:01 a.m.
- He also knows that a minute after creation it is 12:02 a.m.
- And he knows that two minutes after creation is 12:03 a.m.
- And so on.
By virtue of his omniscience, in the eternal now, God knows what time it will be at all moments after creation—even if those moments haven’t occurred yet.
Now let’s ask a question: Supposing that presentism is true and only the present moment is real, what does God know about what exists?
Notice that we’re not asking about what will exist or what did exist. We’re asking about what exists.
If we ask this question at the moment of creation then we will find the following:
- God knows that he is real, and that he exists changelessly, outside of time.
- God knows that the universe is real, and that in time it is currently 12:01 a.m.
But if we ask the same question a minute later, we will find these things:
- God knows that he is real, and that he exists changelessly, outside of time.
- God knows that the universe is real, and that in time it is currently 12:02 a.m.
We have a problem.
When we first asked the question, God eternally and changelessly knew that the moment 12:01 a.m. exists.
The second time we asked the question, God eternally and changelessly knew that the moment 12:02 a.m. exists.
We have a contradiction.
If only a single moment of time exists then 12:01 a.m. and 12:02 a.m. cannot simultaneously be real. Consequently, God can’t simultaneously know that they are real.
For God to first know that 12:01 a.m. is real and later know that 12:02 a.m. is real, God’s knowledge would have to be changeable, and God would have to be experiencing time.
He would not be timeless.
The same problem appears if we ask about what times God knows are not real. For example:
- At the first moment of creation, 12:02 a.m. is not real because it is in the (unreal) future.
- A minute after creation, 12:01 a.m. is not real because it is in the (unreal) past.
If we asked what God knows about the times that are not real then, when we first ask the question, God would know that 12:02 a.m. is not real (and that 12:01 a.m. is real), but when we next ask the question, he would know that 12:01 a.m. is not real (and that 12:02 a.m. is).
Again, God’s knowledge would be changing with time.
The Underlying Logical Problem
This contradiction happens because we are entertaining the following propositions:
- God is real.
- Time is real.
- God knows what is real.
- God is changeless.
- Time consists only of a single, changing moment.
These propositions are not all consistent with each other. Up to four of them can be true, but not all five.
If God knows what is real and what is real changes, then so must God’s knowledge, so God is not changeless.
If you want to accept propositions 1-3 then you must sacrifice either proposition 4 or proposition 5.
Ongoing Change
The same problem reappears when we consider other things God knows.
For example, the way the things in the universe are arranged constantly changes with time.
Even if the total amount of physical energy and mass in the universe stays the same, as modern physics holds, that matter and energy is constantly being rearranged.
Thus there was a time before matter and energy was arranged into stars, a time before it was arranged into living beings, a time before it was arranged into our bodies, etc.
We thus might consider the following:
- At the first moment in time, the matter and energy in the universe was arranged in Configuration 1.
- At the second moment in time, it was arranged in Configuration 2.
- At the third moment in time, it was arranged in Configuration 3.
- And so on.
If we ask our previous question about what God knows is real, it will turn out that—the first time we ask the question—he knows that Configuration 1 is real. But if we ask the same question again, he will know that Configuration 2 is real, etc.
This generates the same kind of problems that we saw above.
God’s Conserving Action
The problem is even worse, because it doesn’t apply just to God’s knowledge. It also applies to his actions.
The Church teaches that the world would not continue to exist unless God sustained it in existence. Thus John Paul II stated:
By creating, God called into being from nothing all that began to exist outside himself. But God’s creative act does not end here. What comes forth from nothing would return to nothing if it were left to itself and not conserved in being by the Creator. Having created the cosmos, God continues to create it, by maintaining it in existence. Conservation is a continuous creation (conservatio est continua creatio) (Audience, May 7, 1986).
This means that, at the first moment of creation, God would generate the universe , with all of the matter and energy in it in Configuration 1.
But then God would have to stop conserving Configuration 1 so that Configuration 2 could come about.
He would then have to stop conserving Configuration 2 so that Configuration 3 could arise.
This would also place God inside of time, since if he were simultaneously conserving all three configurations from outside of time, all three would exist simultaneously from the perspective of the eternal now.
That means all three would be real at once—three different moments of time would exist, contradicting the idea that only a single moment (the present, the “temporal now”) exists.
God would have to be in time if he were to initially create/conserve the moment containing Configuration 1 and then stop doing that to allow Configuration 1 to be replaced by Configuration 2 in the temporal now.
But the Church teaches that God is not in time, so we have another problem.
These aren’t the only problems with the idea that only the present exists. We’ll look at more next time.
(Go to Part 1 | Part 2 | Part 3)
Some people think that only the present is real and that the past and the future don’t exist.