Is there a theoretical maximum for intelligence?

Question

From Artificial Intelligence: A Modern Approach, Third Edition, Chapter 26:

Note that the concept of ultraintelligent machines assumes that intelligence is an especially important attribute, and if you have enough of it, all problems can be solved. But we know there are limits on computability and computational complexity. If the problem of defining ultraintelligent machines (or even approximations to them) happens to fall in the class of, say, NEXPTIME-complete problems, and if there are no heuristic shortcuts, then even exponential progress in technology won't help—the speed of light puts a strict upper bound on how much computing can be done; problems beyond that limit will not be solved. We still don't know where those upper bounds are.

If the textbook's argument is correct, then there may be a strict upper bound to intelligence, meaning that the potential (or damage) of super-intelligence is limited. However, it is contingent on there actually being a theoretical maximum for intelligence.

Is there any literature that suggests that we know for sure whether such a maximum exist? Is the existence of that maximum dependent on our definition of intelligence (so adopting a vague and hand-wavey definition would imply no theoretical maximum, while adopting a strict and formalized definition would imply a theoretical maximum)?

Answer 1

Note that the statement says nothing directly about the limit of intelligence, nor even about the limit of computational intelligence - but about the limit of computing power.

Perhaps the sentence "the speed of light puts a strict upper bound on how much computing can be done" needs a better explanation:

The authors are probably referring to Bremermann's limit, which defines an upper bound in bits per second per kilogram. It is an upper bound on the processing power per unit of time of a computer with a given weight.

There is also Margolus–Levitin theorem which defines an upper limit in operations per second per joule. It is an upper bound on the processing power per unit of energy.

These principles do not define a theoretical limit on computing power, but a practical one. If you'll limit your computer and your energy source to the size and capacity of the earth (or to the those of the universe) - you'll get a very practical limit.

Check the reference section in Wikipedia article Limits to computation