Yeah, I read that book many years ago. He has some interesting and original points, such as
- if a Big Crunch occurs in the right way, then if physics as we know is holds up, this may lead the algorithmic information of the universe to approach infinity, which would give the potential for a lot of interesting things
- potentially we could cause a Big Crunch to occur in the right way, via moving stars around with spaceships
That stuff is very cool to think about, though I'm not as confident as Tipler that our current physics theories are adequate to describe Big Crunches and so forth. Historically physics has changed its fundamental theories every century or so for a while...
Then Tipler couples those interesting observations, and some other ones, with a bunch of discussion about religious views of immortality and so on, that I remember only dimly by this point, except that they went on a long time, contained many interesting observations, and seemed only loosely connected to the physics material....
Even if he's right about immortality and the Big Crunch, I don't quite see how this connects to his discussion of religious views on immortality. Perhaps you could see all these different things as manifestations of some "immortality archetype" existing more deeply than physics or human culture (that's what Jung would have said) but he doesn't really go there either...
The Big Crunch is one kind of Singularity but I've thought more about the nearer-term kind foreseen by Ray Kurzweil and Vernor Vinge and so forth --- i.e. what happens when we create AI minds that create AI minds, etc. that are 10000x more intelligent and capable than our own? That's what I'm working toward with the opencog.org project, and it's a lot more palpable than the Big Crunch !! And I have a sneaking suspicion that once we do have superhuman AGI systems, they will discover that the physical universe is way weirder than even Tipler imagined....