John Brockman’s Edge web-site has an annual feature where he asks a wide array of scientists and others how they would answer a hopefully thought-provoking question. Last year the question was What Do You Believe Is True Even Though You Cannot Prove It? This year it’s What Is Your Dangerous Idea?
There are responses to this question from 117 different people, a large fraction of them psychologists or cognitive scientists. Among the responses from physicists, several deal with the Landscape as a dangerous idea. Susskind takes credit for it, noting “I have been accused of advocating an extremely dangerous idea”, and that some of his colleagues believe it will lead to the end of science, leaving no way to defend physics as a truer path to knowledge than religion. He proudly describes the anthropic Landscape idea as “spreading like a cancer.”
On the opposite side of the issue, Brian Greene emphasizes the dangers of the Landscape philosophy:
When faced with seemingly inexplicable observations, researchers may invoke the framework of the multiverse prematurely — proclaiming some or other phenomenon to merely reflect conditions in our bubble universe — thereby failing to discover the deeper understanding that awaits us.
Paul Steinhardt is more emphatic about these dangers:
I think it leads inevitably to a depressing end to science. What is the point of exploring further the randomly chosen physical properties in our tiny corner of the multiverse if most of the multiverse is so different. I think it is far too early to be so desperate. This is a dangerous idea that I am simply unwilling to contemplate.
He also has his own “dangerous idea”, about a cyclic model of the universe explaining the small size of the cosmological constant. Lawrence Krauss gives his own version of an explanation of the danger that the Landscape will lead to an end-point for theoretical physics:
… all so-called fundamental theories that might describe nature would be purely “phenomenological”, that is, they would be derivable from observational phenomena, but would not reflect any underlying grand mathematical structure of the universe that would allow a basic understanding of why the universe is the way it is.
Some other interesting contributions from physicists come from Philip Anderson, who has some speculative comments about dark matter and dark energy, Lee Smolin, who discusses the possibility of natural selection having something to do with fundamental laws, and Carlo Rovelli, who remarks that we have still not completely absorbed the revolutionary ideas of 20th century physics:
I think that seen from 200 years in the future, the dangerous scientific idea that was around at the beginning of the 20th century, and that everybody was afraid to accept, will simply be that the world is completely different from our simple minded picture of it. As the physics of the 20th century had already shown.
What makes me smile is that even many of todays “audacious scientific speculations” about things like extra-dimensions, multi-universes, and the likely, are not only completely unsupported experimentally, but are even always formulated within world view that, at a close look, has not yet digested quantum mechanics and relativity!