by Chet Raymo
"It is one of Albert Einstein's most-often quoted quotes: "The most incomprehensible thing about the world is that it is at all comprehensible." Is the world comprehensible? Apparently at least partially so. Consider the NASA solar eclipse atlas I referenced the other day. It is possible to calculate the precise locations and times for solar eclipses thousands of years into the future and past. That's comprehensibility for you.
Of course, there are still things we do not comprehend, such as consciousness or the development of organisms, but there is no good reason to suppose those things are intrinsically beyond human understanding. The whole of modern technological civilization and medicine is a monument to comprehensibility.
Why? Why this strange consonance between the world and the human mind? For centuries the answer was simple. God created a world of space and time, a finite mirror, so to speak, of his own intelligence. He created humans in his own likeness. Human intelligence partook of the intelligibility of God. Everything in the closed, human-centered cosmos was ordered in his likeness. The world was comprehensible because it was made that way- for us to comprehend.
Then, in the 16th and 17th centuries, came the great disruption, which Alexandre Koryé described in his seminal 1957 book "From the Closed World To the Infinite Universe." Daring thinkers resurrected the Greek idea that the universe might be infinite in extent and eternal in duration- no boundaries in space, no beginning or end in time. It was a radical thought, heretical really, but it meshed well with what the astronomers and physicists were learning about the world we live in. As the poet John Donne wrote:
The element of fire is quite put out,
The sun is lost, and th' earth, and no man's wit
Can well direct him where to look for it.
And freely men confess that this world's spent,
When in the planets and the firmament
They seek so many new; they see that this
Is crumbled out again to his atomies.
'Tis all in pieces, all coherence gone,
All just supply, and all relation."
Of course, it wasn't as bad as all that. Galileo and Newton provided a new coherence. The physical world itself took on two characteristics of the Godhead- omnipresence and everlasting life. Everything unfolded not in accordance with the divine will, but according to eternal and immutable laws of nature. The Divine Artifex, master craftsman, in Koyré's words, was replaced by the Dieu fainéant, a lazybones God with nothing to do. And the comprehensibility of the world became- well, as Einstein said- incomprehensible. But... things were about to get more complicated.
Both theories had strengths and weaknesses. For example, the big bang successfully accounted for the known abundances of hydrogen and helium in the universe but posited an embarrassing beginning that could not be explained. The steady state theory avoided the stumbling block of a universe that seemed to come from nowhere but replaced it with many little unexplained beginnings (those particles of matter appearing continuously from nothing). Yet the big bang theory made one prediction that was testable: if the universe began in a blaze of luminosity, a degraded remnant of that radiation should still permeate the cosmos, and the precise spectral distribution of this microwave-frequency background could be calculated.
Then, that very year I started teaching, the cosmic microwave background radiation was serendipitously discovered by Arno Penzias and Robert Wilson, with precisely the predicted spectrum, a triumph of comprehensibility. The universe- space and time- had an apparent beginning! For some people, this extraordinary development re-opened the door to a creator God, whose intelligence is the source for the intelligibility of the world. Koyré may have anticipated this. In his final paragraph he wrote: "The infinite Universe of the New Cosmology, infinite in Duration as well as in Extension, in which eternal matter in accordance with external and necessary laws moves endlessly and aimlessly in eternal space, inherited all the ontological attributes of Divinity. Yet only those- all the others the departed God took away with Him."
What others? Personhood. Love. Justice. And intelligence. Intelligence that is the source of the intelligibility of the world.
But for Einstein, and many of us here, the mathematical singularity which is the big bang is an opaque barrier. To say the universe is created by God conveys no more information than to say it is created by X. We learned to live without Koyré's Dieu fainéant, the lazybones God who had nothing to do, and see no reason to bring him out of retirement. So why is the universe comprehensible?
First, one very important feature of consciousness has already been comprehended. We can say with a high degree of confidence that there is no ghost in the machine, that consciousness is an emergent physio-chemical property of the material brain. Whether consciousness is deterministic or involves some measure of quantum uncertainty remains to be seen, but I find Roger Penrose's argument for quantum uncertainty unconvincing. For the moment, Ockham's Razor rules.
Second, we can study emergent consciousness by observing other organisms, from sea snails to chimpanzees. That is, in principle, we can build up an understanding of human consciousness incrementally. This assumes, of course, that human consciousness differs from that of other organisms only in complexity, not kind. Again, for the moment, the Razor rules.
Third, as I mentioned here once before, a project is underway to fully map the neuronal structure of the human brain, at which point it should be possible to construct an operational electronic analog of the brain. Will such machines be conscious? Google "artificial consciousness" and you'll find arguments for both sides. At the very least we will pare away some of the incomprehensibility.
Fourth, we may already have created a "conscious" machine: the internet, which approaches the human brain in its degree of interconnected complexity. It is continuously "aware," sensitive to millions of sensory inputs- touch, vision, hearing, smell, and for all I know even taste. I can ask a question in human language or tap an icon and instantly have a response from the internet's vast memory. The internet and its myriad of input/output devices mimic enough of the aspects of human consciousness for us to be increasingly confident that consciousness is not intrinsically beyond in principle understanding.
And isn't in principle understanding all we ask of science?"