I believe the Fermi Paradox[1] is very compelling evidence that the evolution of computation is logistic[2] and further that saturation comes before practical interstellar travel. Otherwise I feel it's likely we would have already seen evidence of Clarke's Overmind[3].
That intelligence becomes increasingly specialized rather than general is a reasonable explanation for why such saturation may happen (in a hand wavy way).
I also think that much of the discussion about the Singularity, downloading brains, etc, makes many anthropomorphic assumptions that are entirely unjustified. I suspect it's more likely that we'll have better luck building artificial chemical brains than we ever will simulating some captured representation of the state of a human brain on a digital computer.
On the upside, if computation's growth is logistic then certainly we're in the exponentiation portion right now, which means humanity still is likely to see generations of at least near linear improvement. We may be essentially trapped in this solar system, but we'll likely have quite astounding information processing capabilities.
That intelligence becomes increasingly specialized rather than general is a reasonable explanation for why such saturation may happen (in a hand wavy way).
I also think that much of the discussion about the Singularity, downloading brains, etc, makes many anthropomorphic assumptions that are entirely unjustified. I suspect it's more likely that we'll have better luck building artificial chemical brains than we ever will simulating some captured representation of the state of a human brain on a digital computer.
On the upside, if computation's growth is logistic then certainly we're in the exponentiation portion right now, which means humanity still is likely to see generations of at least near linear improvement. We may be essentially trapped in this solar system, but we'll likely have quite astounding information processing capabilities.
1: http://en.wikipedia.org/wiki/Logistic_function
2: http://en.wikipedia.org/wiki/Fermi_paradox
3: http://en.wikipedia.org/wiki/Childhoods_End (a good book if you forgive it a few mystical characterizations of psychic powers)