People who claim that the earth is younger than it is (4.54 ± 0.05 billion years) tend to do so for two reasons: either because they claim the evidence points to it or because it was created recently but made to look as it were old. Considering that all the evidence shows the universe to be 13.75 (± 0.11) billion years, a claim that it is literally millions of times younger requires massive ignorance of obvious observations – such as starlight or canyons cut into bedrock. But let’s consider the other common argument – that the universe was only made to appear young. Perhaps the stars were put in place with the light beams already in progress. That is an interesting philosophical question. What are the implications of an Intelligently Designed universe?
To avoid taking sectarian sides, let’s call our creator Bob the Universe Builder. How would Bob’s universe-creating activity change the way we look at the world? Let’s consider a few scenarios:
Some people believe that Bob “got things started” via the Big Bang or some other mysterious event, and then let things run on their own, much as they would in a purely naturalistic universe. In that case, cosmology would certainly be different, but biology could generally be left alone. This view was plausible until recently, when physicists and cosmologists began thinking about and finding answers for how the Big Bang got started and why the laws of nature are what they are. Suddenly the starting point is not so mysterious as to need a supernatural explanation. What is the creation theorist to do – retreat once again to the next frontier of scientific discovery? Perhaps we can make a more general argument.
Whether the universe was created 13 billion or 6 thousand years or yesterday, we can generalize the creationist argument and make some conclusions about it. Suppose we grant that the universe looks as if it evolved purely by natural laws, but in fact some intelligent agent created it more recently. What would that imply?
Let’s first consider the universe going forward. If the universe is naturalistic from the present onwards (gravity causes rocks to fall, horses don’t become unicorns, etc.), then we can assume that it will remain so in the future. So as far as our understanding of new phenomena around us, the existence of a non-interventionist creator makes no difference. But what about the past? If we assume that all the evidence points to a natural universe (for example the stars look billions of years old, even if they were only put up there yesterday), then it makes no difference whether the universe only looks natural or it really is natural.
Before he could create the universe, Bob would have to calculate the precise makeup of the universe on his computer (which could be his “brain” – the details are irrelevant) to determine the initial state of his Creation. For example, if he creates the universe after the Triassic period, he will have to figure out where to place all the dinosaur fossils. If he wanted to maintain the pretense of age, he could not place them just anywhere. He would have to carefully arrange sedimentary layers to simulate geological processes.
The only way to do this consistently would be to simulate the entire history of the observable universe on his computer. There is no way to shortcut the process. So, for example, if a dinosaur fossil is 200 million years old, Bob must calculate its gravitational effect on every atom and subatomic particle in a light cone expanding to 200 million light years over 200 million years. Alternatively, consider the implication for evolution: even if did not happen in “real” reality, to create a plausible explanation for the variety of life on earth and their fossil predecessors, Bob would have to calculate the form of every ancestor by playing out the life of every plant, animal and bacteria in his “virtual” earth to derive their fossils and their present form. Because the present state of any object in the universe is the total of all the interactions of that object with all the other objects in its sphere of influence, and there is no way to know the sum of all these states without calculating all of them sequentially.
To avoid glaring inconsistencies from being discovered by scientists, Bob would have to calculate the interaction of every entity in the universe with every other entity in its causal sphere to the minutest level of detail. And given the sub-atomic perspective granted by modern science, that detail must be very fine indeed. This would mean that there couldn’t be any observable difference between a simulation of the universe and the real thing. Whether the universe was ever a simulation in someone’s “imagination” or is simulation today makes no observable difference and this has no relevance to our understanding of reality.
My conclusion from this chain of thought is this: There is no essential difference between “Young Earth” Creationism and the more “respectable” theory of Big Bang Creationism. Neither is there any point speculating about a perfectly simulated universe (aka various theories that the universe exists “in the mind of God”.) The only logical conclusion is to regard the universe as always having been purely naturalistic.