Monday, June 14, 2010

Kant, Gödel, & Rees

D'oh, we may never decode the universe - Times Online Jonathan Leake 42 COMMENTS Understanding vast cosmic events such as galactic collisions is one of science's greatest challenges, says Lord Rees

SOME of the greatest mysteries of the universe may never be resolved because they are beyond human comprehension, according to Lord Rees, president of the Royal Society.
Rees suggests that the inherent intellectual limitations of humanity mean we may never resolve questions such as the existence of parallel universes, the cause of the big bang, or the nature of our own consciousness.
He even compares humanity to fish, which swim through the oceans without any idea of the properties of the water in which they spend their lives.
“A ‘true’ fundamental theory of the universe may exist but could be just be too hard for human brains to grasp,” said Rees, who is also the astronomer royal.
Top of Form
Bottom of Form
“Just as a fish may be barely aware of the medium in which it lives and swims, so the microstructure of empty space could be far too complex for unaided human brains.”
Rees’s thesis could prove highly provocative to other scientists, especially those who have devoted their careers to understanding such mysteries.
He is well placed to understand the potential limitations of science. Besides heading Britain’s premier scientific organisation, he is also professor of cosmology at Cambridge University, where he is one of Britain’s most respected astrophysicists. He is currently delivering the annual BBC Reith lectures.
Rees’s warning, in a Sunday Times interview, is partly prompted by the failure of scientists working on the greatest problem of modern physics — to reconcile the forces that govern the behaviour of the cosmos, including planets and stars, with those that rule the so-called microworld of atoms and particles.
Rees points out how Albert Einstein was able to use mathematical theories developed in the early 19th century to build his 1915 theory of general relativity, describing how gravity controlled stars and planets.
Similarly, early 20th-century physicists such as Paul Dirac used “off-the-shelf” mathematical systems when devising quantum theory, which describes how nature works at a sub-atomic level.
The problem faced by their successors is that the two theories are deeply contradictory — and no one can find the mathematical tools needed to bring them together into a “unified theory”.
Rees points out that thousands of scientists have been working on this problem for several decades and are still nowhere near an answer.
“There are powerful reasons to suspect that space has a grainy structure but on a scale a trillion trillion times smaller than atoms. Solving how this might work is crucial for 21st-century science,” he said.
Rees believes the most promising idea is “string theory” which suggests that the particles that make up atoms are “woven from space itself”. Such particles, he suggests, could exist in 10 or 11 dimensions. Humans, by contrast, can experience only the three spatial dimensions plus time. He adds that there could even be other 3-D universes “embedded alongside ours”.
“In theory, there could be another entire universe less than a millimetre away from us, but we are oblivious to it because that millimetre is measured in a fourth spatial dimension and we are imprisoned in just three,” he said.
Such ideas sound extraordinary but Rees wonders if they can ever be proved. He suggests humanity may have reached the limits of comprehension.
“Some aspects of reality — a unified theory of physics or a full understanding of consciousness — might elude us simply because they’re beyond human brains, just as surely as Einstein’s ideas would baffle a chimpanzee,” he said.
Other scientists are more optimistic. Brian Cox, the BBC science presenter and physics professor who was awarded an OBE yesterday, said: “The idea that certain things are beyond us is quite a bleak one and history does show that we can eventually overcome the most difficult of problems.”
The mind boggles
The scientific mysteries that may be beyond us include
* Multiple dimensions — string theory suggests space has up to 11 dimensions, but mathematicians have struggled to prove this
* Consciousness — scientists suggest consciousness derives from chemical reactions in the brain but cannot explain how this might generate a sense of self
* Are we real? — Rees and other physicists have suggested the universe and humanity are part of a giant computer simulation as seen in the Matrix films
People not smart enough to understand universe: scientist Toronto Sun By QMI Agency A top British scientist says we may never know all the secrets of the universe because, quite simply, we're just not smart enough. ... Has the human brain reached its limit of understanding?‎ - Limitations of the human brain mean we may never understand the ...‎ - Daily Mail
This is the week of my annual lecture, which as regular readers know is on twenty first century enlightenment. Madeleine Bunting has kindly written a piece.

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