## Thursday, August 9, 2018

### Two puzzles about pain and time

Supposing the growing block theory of time is correct and you have a choice between two options.

1. You suffer 60 minutes of pain from 10:30 pm to 11:30 pm.
2. You suffer 65 minutes of pain from 10:50 pm to 11:55 pm.

Clearly, all other things being equal, it is irrational to opt for B. But supposing growing block theory is true, there are only past and present pains, and no future pains, so why is it irrational to opt for B?

Well, maybe rationality calls on us to make future reality be better, and we have:

1. If you opt for A, then at 11:55 reality will contain 60 minutes of pain

2. If you opt for B, then at 11:55 reality will contain 65 minutes of pain.

Opting for B will make reality worse (for you) at 11:55, so it seems irrational to choose B. However, we also have facts like these:

1. If you opt for A, then at 11:30 reality will contain 60 minutes of pain.

2. If you opt for B, then at 11:30 reality will contain 55 minutes of pain.

Thus, opting for A will make reality worse at 11:30. Why should the 11:55 comparison trump the 11:30 comparison?

One answer is this: The 11:55 comparison continues forever. If you choose B, then reality tomorrow, the day after tomorrow, and so on will be worse than if you choose B, as on all these days reality will contain the 65 minutes of past pain instead of the mere 60 minutes if you choose A.

However, this answer isn’t the true explanation. For suppose time comes to an end tonight at midnight. Then it’s still just as obvious that you should opt for A instead of B. However, now, it is only during the ten minute period after 11:50 pm and before midnight that reality-on-B is worse than reality-on-A, while reality-on-A is better than reality-on-B during the whole of the 80 minute period strictly between 10:30 pm and 11:50 pm. It is mysterious why the comparison during the 10 minute period starting 11:50 pm should trump the comparison during the 80 minute period ending at 11:50 pm.

I suppose the growing blocker’s best bet is to say that later comparisons always trump earlier ones. It is mysterious why this is the case, though.

The story is also puzzling for the presentist, as I discuss here. But there is no problem for the eternalist: on B reality always contains more pain than on A.

However, there is a different puzzle where the growing blocker can tell a better story than the eternalist. Suppose you will live forever, and your choice is between:

1. You will feel pain from 10 pm to 11 pm every day starting tomorrow
2. You will feel pain from 9 am to 11 am every day starting tomorrow.

Intuitively, you should go for C rather than D. But on eternalism, on both C and D reality includes an equal infinite number of hours of pain. But on growing block, after 9 am tomorrow, reality will be worse for you if you choose D rather than C. Indeed, at every time after 9 am, on option D reality will contain at least twice as much pain for you as on option C (bracketing any pains prior to 9 am tomorrow). So it’s very intuitive that on growing block you should choose C.

Maybe, though, the eternalist can say that utility comparisons involving infinities just are going to be counterintuitive because infinities are innately counterintuitive, as our intuitions are designed/evolved for dealing with finite cases. Moreover, we can tell similar puzzles involving infinities without involving theories of time. For instance, suppose an infinite line of people numbered 1,2,3,…, all of whom are suffering headaches, and you have a choice whether to relieve the headache of the persons whose number is even versus the headache of the persons whose number is prime. The intuition that C is better than D seems to be exactly parallel to the intuition that it’s better to benefit the even-numbered rather than the prime-numbered. But the latter intuition is not defensible. (Imagine reordering the people so now the formerly prime-numbered are even-numbered and vice-versa. Surely such a reordering shouldn’t make any moral difference.) So perhaps we need to give up the intuition that C is better than D?

Bogdan Faul said...

Dr. Pruss,

I think that eternalist could reply in something like the following way:

In the living forever scenario, we should not compare the total amount of pain, but its density. Imagine that there are two scenarios C* and D*.

C* you will feel pain for 6 hours a day forever (from 9 to 15).
D* you will feel pain for 12 hours a day forever (from 9 to 21).

Thus, C* pain density is 2 times lower than D* pain density. Even if our measuring interval is not fitted to days perfectly (e.g., I choose to measure pain density in 1-day and a half), the more interval we take, the closer to 2 will be our density difference.

Alexander R Pruss said...

That's a good idea. I think it works if we have long-term memory, which imposes an order on our experiences. But what if we had no memory (or only short-term memory)? I doubt density would matter then. Maybe then it would be more like the case of infinitely many people, some in pain and some not?

Philip Rand said...

Each theory of time (in isolation) is incorrect, i.e. pastism, presentism, eternalism.

A. You probably will suffer 60 minutes of pain from probably 10:30 pm to probably 11:30 pm.
B. You probably will suffer 65 minutes of pain from probably 10:50 pm to probably 11:55 pm.

Philip Rand said...

To be precise:

A. You probably will probably suffer probably 60 minutes of pain from probably 10:30 pm to probably 11:30 pm.
B. You probably will probably suffer probably 65 minutes of pain from probably 10:50 pm to probably 11:55 pm.

Philip Rand said...

. For instance, suppose an infinite line of people numbered 1,2,3,…, all of whom are suffering headaches, and you have a choice whether to relieve the headache of the persons whose number is even versus the headache of the persons whose number is prime. The intuition that C is better than D seems to be exactly parallel to the intuition that it’s better to benefit the even-numbered rather than the prime-numbered

A quick calculation using the Benford Law & a logarithmic 1/x power law would suggest that the prime numbered people should get the pain relief. This puzzle is not similar to the C/D puzzle. The interesting question is why they are not similar?

Bogdan Faul said...

Dr. Pruss,

It seems to me that if one believes that metaphysical criterion of the persistence of personal identity over time is independent of memory, it is more rational for him/her to choose the scenario with lower pain density anyway.

Given that we have a short-term memory, and that personal identity is independent of memory, I think that the choice between C* and D* is a choice between

C** you will feel pain for 6 hours a day forever, but will not remember it.
D** you will feel pain for 12 hours a day forever, but will not remember it.

Anyway, it is more rational to choose less pain than more pain, and in the living forever scenario by more pain, I mean higher pain density. I think that beliefs about the metaphysical conditions of the persistence of personal identity over time are relevant in practical choices.

But we can alter the story a little bit:

C# you will feel pain for 6 hours a day forever, but you will remember only suffering moments.
D# you will feel pain for 12 hours a day forever, but you will not remember suffering moments.

My intuitions say that I should go for D#, even though pain density in this scenario is two times higher than in C#. So in my practical decisions, metaphysical beliefs about personal identity are not crucial, but not irrelevant.

Philip Rand said...

Bogdan Faul

C# you will feel pain for 6 hours a day forever, but you will remember only suffering moments.
D# you will feel pain for 12 hours a day forever, but you will not remember suffering moments.

C#: the degree of disorder of pain is low with a large gradient content of pain.
D#: the degree of disorder of pain is high with no gradient content of pain.

Does this analysis make your choice easier?

Philip Rand said...

C** you will feel pain for 6 hours a day forever, but will not remember it.
D** you will feel pain for 12 hours a day forever, but will not remember it.

C**:the degree of disorder of pain is high with no gradient content of pain.
D**:the degree of disorder of pain is high with no gradient content of pain.

Does this analysis make your choice easier?

Philip Rand said...

Can you observe the logical trajectory you should reach with:

C* you will feel pain for 6 hours a day forever (from 9 to 15).
D* you will feel pain for 12 hours a day forever (from 9 to 21).