The question “Why am I not somebody else?” is nonsensical because for almost anybody I am somebody else.
More precisely: “I” refers to some numerically unique entity x. Thus “I is someone else” means x = -x which is an outright contradiction and we shouldn’t waste our time asking why contradictions aren’t the case.
It only sounds nonsensical because of the words in which it’s asked. The question raised by anthropic reasoning isn’t “why do I live in a time I call the present” (to which, as you say, the answer is linguistic—of course we’d call our time the present) but rather “why do I live in the year 2010?” or, most precisely of all, “Given that I have special access to the subjective experience of one being, why would that be the experience of a being born in the late 20th century, as opposed to some other time?”
That may still sound tautological—after all, if it wasn’t the 20th century, it’d be somewhen else and we’d be asking the same question—but in fact it isn’t. Consider these two questions:
Why am I made out of carbon, as opposed to helium?
Why do I live in the 20th century, as opposed to the 30th?
The correct answer to the second is not saying, “Well, if you were made out of helium, you could just ask why you were made out of helium, so it’s a dumb question”, it’s pointing out the special chemical properties of carbon. Anthropic reasoning suggests that we can try doing the same to point out certain special properties of the 20th century.
The big difference is that the first question can be easily rephrased to “why are people made out of carbon and not of helium”, but the second can’t. But that difference isn’t enough to make the second tautological or meaningless.
I think maybe some of this was meant for the comment above me.
That said I think the “I” really is the source of some if not all of these confusions and:
The big difference is that the first question can be easily rephrased to “why are people made out of carbon and not of helium”, but the second can’t. But that difference isn’t enough to make the second tautological or meaningless.
I think the difference is exactly enough to make the second one tautological or meaningless. What you have to do is identify some characteristics of “I” and then ask: Why do entities of this type exist in the 20th century, as opposed to the 30th? If you have identified features that distinguish 20th century people from 30th century people you will have asked something interesting and meaningful.
If ‘you’ lived in the 30th century you’d have different memories, at the very least, and thus ‘you’ would be a different person. That is to say, you wouldn’t exist.
On the other hand, if the brain is reasonably substrate-independent, you could be exactly the same person if you were made out of helium.
More precisely: “I” refers to some numerically unique entity x. Thus “I is someone else” means x = -x which is an outright contradiction and we shouldn’t waste our time asking why contradictions aren’t the case.
It only sounds nonsensical because of the words in which it’s asked. The question raised by anthropic reasoning isn’t “why do I live in a time I call the present” (to which, as you say, the answer is linguistic—of course we’d call our time the present) but rather “why do I live in the year 2010?” or, most precisely of all, “Given that I have special access to the subjective experience of one being, why would that be the experience of a being born in the late 20th century, as opposed to some other time?”
That may still sound tautological—after all, if it wasn’t the 20th century, it’d be somewhen else and we’d be asking the same question—but in fact it isn’t. Consider these two questions:
Why am I made out of carbon, as opposed to helium?
Why do I live in the 20th century, as opposed to the 30th?
The correct answer to the second is not saying, “Well, if you were made out of helium, you could just ask why you were made out of helium, so it’s a dumb question”, it’s pointing out the special chemical properties of carbon. Anthropic reasoning suggests that we can try doing the same to point out certain special properties of the 20th century.
The big difference is that the first question can be easily rephrased to “why are people made out of carbon and not of helium”, but the second can’t. But that difference isn’t enough to make the second tautological or meaningless.
I think maybe some of this was meant for the comment above me.
That said I think the “I” really is the source of some if not all of these confusions and:
I think the difference is exactly enough to make the second one tautological or meaningless. What you have to do is identify some characteristics of “I” and then ask: Why do entities of this type exist in the 20th century, as opposed to the 30th? If you have identified features that distinguish 20th century people from 30th century people you will have asked something interesting and meaningful.
How would you characterise and answer this question:
Why do I like to make paperclips, as opposed to other shapes into which I could form matter?
If ‘you’ lived in the 30th century you’d have different memories, at the very least, and thus ‘you’ would be a different person. That is to say, you wouldn’t exist.
On the other hand, if the brain is reasonably substrate-independent, you could be exactly the same person if you were made out of helium.
A world different enough from this that you were made out of helium would probably leave you with different memories.