Now sit him down on his college dorm twin mattress and show him photographs from his future.
By doing this, it is almost certain that these photographs won’t be from his future unless you are a superintelligence and very carefully chose both that person and those photographs knowing that his future contingent upon him seeing those photographs = the depicted future.
Those photographs can only be correct to the extent that he allows them to be correct. Not every such system has a fixed point, and for some selections of person this may be simply impossible.
But is this even possible for any predictee at all? After all, his future is also your future, and you would need to be able to predict your own actions and their consequences in perfect detail as well as that of the rest of the universe.
Can a system have sufficient computing power to do this, while still being embedded in the universe that is being predicted in perfect detail? This seems a pretty big assumption, and it’s not just an assumption about a specific universe (which we can just posit as a hypothetical) but a mathematical assumption about the degree to which complex computational systems (e.g. able to prove theorems of arithmetic) are capable of perfectly predicting their own future behaviour.
By doing this, it is almost certain that these photographs won’t be from his future unless you are a superintelligence and very carefully chose both that person and those photographs knowing that his future contingent upon him seeing those photographs = the depicted future.
Those photographs can only be correct to the extent that he allows them to be correct. Not every such system has a fixed point, and for some selections of person this may be simply impossible.
But is this even possible for any predictee at all? After all, his future is also your future, and you would need to be able to predict your own actions and their consequences in perfect detail as well as that of the rest of the universe.
Can a system have sufficient computing power to do this, while still being embedded in the universe that is being predicted in perfect detail? This seems a pretty big assumption, and it’s not just an assumption about a specific universe (which we can just posit as a hypothetical) but a mathematical assumption about the degree to which complex computational systems (e.g. able to prove theorems of arithmetic) are capable of perfectly predicting their own future behaviour.
To me, it seems an unlikely proposition.