I don't know whether physicist David Deutsch's optimism expressed in his new book, "The 'Beginning of Infinity," is justified. I'm only about a quarter of the way through it, so maybe his later chapters imply more of a downer that what I've read so far.
His basic thesis, though, is both inspiring and believable. There are no limits to knowledge. Human life -- individual or collective -- is a never-ending journey on the path to more.
Whenever there has been progress, there have been influential thinkers who denied that it was genuine, that it was desirable, or even that the concept was meaningful. They should have known better.
There is indeed an objective difference between a false explanation and a true one, between chronic failure to solve a problem and solving it, and also between wrong and right, ugly and beautiful, suffering and its alleviation -- and thus between stagnation and progress in the fullest sense.
In this book I argue that all progress, both theoretical and practical, has resulted from a single human activity: the quest for what I call good explanations.
Though this quest is uniquely human, its effectiveness is also a fundamental fact about reality at the most impersonal, cosmic level -- namely that it conforms to universal laws of nature that are indeed good explanations. This simple relationship between the cosmic and the human is a hint of a central role of people in the cosmic scheme of things.
(Note: from what I can tell, when Deutsch says "people" he really means evolved conscious beings, who could be aliens quite different from us.)
For a long time I was so much into supposedly ineffable meditation and mysticism, I rejected the idea that good explanations are the key to understanding reality. But I've changed, and reading Deutsch's book is changing me further.
I mean, think about it: what's the difference between a fundamentalist religious belief in God that can't be challenged because it is faith-based, and someone's claim that "I know what ultimate truth is, but I can't explain it to you"?
The astrophysicist Martin Rees has speculated that somewhere in the universe 'there could be life and intelligence out there in forms we can't conceive. Just as a chimpanzee can't understand quantum theory, it could be there are aspects of reality that are beyond the capacity of our brains.'
But that cannot be so. For if the 'capacity' in question is mere computational speed and amount of memory, then we can understand the aspects in question with the help of computers -- just as we have understood the world for centuries with the help of pencil and paper.
As Einstein remarked, 'My pencil and I are more clever than I.' In terms of computational repertoire, our computers -- and brains -- are already universal.
But if the claim is that we may be qualitatively unable to understand what some other forms of intelligence can -- if our disability cannot be remedied by mere automation -- then this is just another claim that the world is not explicable.
Indeed, it is tantamount to an appeal to the supernatural, with all the arbitrariness that is inherent in such appeals, for if we wanted to incorporate into our world view an imaginary realm explicable only to superhumans, we need never have bothered to abandon the myths of Persephone and her fellow deities.
So human reach is essentially the same as the reach of explanatory knowledge itself.