Many forms of the anthropic argument just don’t hold water. You can bend over backwards to find the fault in the logic, and I applaud your effort here to do that.
I think an easier way to dismiss the set of arguments is to think of two different cases, one in which there are few observers and one in which there are many, and then ask how the subjective observer could use the anthropic argument to distinguish these two. She can’t.
Then these arguments can be discounted with the line of reasoning that says if a theory can’t tell you which world you’re in, then it predicts everything, so it tells you nothing. (Evidence for a given theory is the observation of an event that is more likely to occur if the theory is true than if it is false.)
Consider the argument that since we’re observers at a relatively early time in human technological development, this means we should update that there is a higher probability that humans don’t persist for a hugely long time after. This argument kind of makes sense when worded exactly as “if humans persisted for billions of years, what is the probability I would be a human in the first .005 billion years?”.
But the way to test if that line of reasoning works is to ask, suppose you have two realities, one in which humans persisted for .1 billion years and one in which humans persisted for 100 billion years. How could the set of observers at .005 billion years use the anthropic argument to distinguish between the two? They couldn’t. The anthropic argument has no power to select among these two realities; the anthropic principle predicts exactly the same set of observations for the set of observers at time point .005 billion years for the two different realities. Likewise, consider that there are 50 red rooms or 5000 red rooms, and one blue door. The person who wakes in the blue room has no evidence about the number of red rooms, because her observations (a blue room) are exactly the same for both cases.
Many forms of the anthropic argument just don’t hold water. You can bend over backwards to find the fault in the logic, and I applaud your effort here to do that.
I think an easier way to dismiss the set of arguments is to think of two different cases, one in which there are few observers and one in which there are many, and then ask how the subjective observer could use the anthropic argument to distinguish these two. She can’t.
Then these arguments can be discounted with the line of reasoning that says if a theory can’t tell you which world you’re in, then it predicts everything, so it tells you nothing. (Evidence for a given theory is the observation of an event that is more likely to occur if the theory is true than if it is false.)
Consider the argument that since we’re observers at a relatively early time in human technological development, this means we should update that there is a higher probability that humans don’t persist for a hugely long time after. This argument kind of makes sense when worded exactly as “if humans persisted for billions of years, what is the probability I would be a human in the first .005 billion years?”.
But the way to test if that line of reasoning works is to ask, suppose you have two realities, one in which humans persisted for .1 billion years and one in which humans persisted for 100 billion years. How could the set of observers at .005 billion years use the anthropic argument to distinguish between the two? They couldn’t. The anthropic argument has no power to select among these two realities; the anthropic principle predicts exactly the same set of observations for the set of observers at time point .005 billion years for the two different realities. Likewise, consider that there are 50 red rooms or 5000 red rooms, and one blue door. The person who wakes in the blue room has no evidence about the number of red rooms, because her observations (a blue room) are exactly the same for both cases.