Mark Fancey writes: > You say that you are more careful now (and everyone should always be > more careful!); but is it not, in fact, irrelevant? This is because > the worlds in which you cause great tragedy exist even before you > arrive at a branch point that could take you to them.
I think what you mean is, that all branches get taken, so even if I try to change my actions everything will still happen. A variant on this idea is simply that the MWI is deterministic. This is true, in the MWI there is no chance and it is as deterministic as the classical Newtonian clockwork universe. However I believe that free will is compatible with determinism. We just had a large discussion on this topic. Look up "compatibilism" in google to get some references to this. Given that I have free will, it manifests in the MWI by changing the probability or measure of the branches. Yes, all the branches still exist. But if I drive carefully, the branches where bad things happen will have lower measure than the branches where good things happen. This is how I view my actions as affecting the multiverse. > It is also my understanding that time travel (travelling along > timelike curves) is quite possible; I have always grown up being told > that it is not possible. Altering my worldview on that one is taking > some time! To me it is the ultimate surveillance tool and makes me > quite jittery! I don't know, I would say that since anything can happen, we can mimic the effect of time travel. A person can pop into existence with memories of the future. However, a person can also pop into existence with false memories of a non-existent future. Probably the latter is more probable. Hal Finney