Lawrence Krauss is a notable theoretical physicist who I'd heard of, but I didn't really know much about him until I watched a three hour You Tube video of Krauss interviewing Robert Sapolsky about his book, Determined, which explores the illusion of free will. If you're into this sort of thing, and have some time to spare, the interview is fascinating.
Sapolsky (on the left) and Krauss talked about their personal lives and approach to science before getting into Sapolsky's book. I loved how these Jewish atheists each had mothers who dearly wanted them to become medical doctors, even after they were successes in their fields.
Krauss told a story about how he'd gotten an academic appointment to a medical school department for a reason I can't recall. When he mentioned this to his mother, she said something like, "That's wonderful. It will help you when you apply to medical school." Great to know that Jewish mother jokes have a grounding in reality.
Near the end of the interview Krauss mentioned his newest book. That made me head to Amazon and look for it.
When I found The Edge of Knowledge:Unsolved Mysteries of the Cosmos, both the title and my new acquaintance with Krauss through the video drew me to order the book. I've read part of it and am enjoying the readable overview of what's currently known about Time, Space, Matter, Life, and Consciousness (the key chapters) and the mysteries in these areas.
What I like is both the scientific knowledge in the book, and the descriptions of scientific methodology that are both explicitly stated and implied. Below are passages from the initial chapters along the methods front.
I love science, so I love what Krauss says here. He accurately presents science and scientists as open-minded, but not so open that critical thinking falls out. Science and scientists adore mysteries, questions, not-knowing. There's no better way to understand the nature of reality, for sure.
Three of the most important words in science are: "I don't know." Therein lies the beginning of enlightenment because not knowing implies a universe of opportunities -- the possibility of discovery and of surprise.
If history is any guide, there is a lot more about the universe that we don't know than we do. Sometimes that is taken to imply that we know almost nothing. In truth, we know a great deal, and that guides us in our search to learn more. But the recognition that many cosmic mysteries still remain provides a long-term hopefulness to the scientific enterprise, not to mention a kind of cosmic job security.
The mysteries are moving targets, and they define the scientific forefront -- the threshold of the unknown. To explore that threshold is to gain a deeper understanding of just how far science has progressed. That is the purpose of this book.
Because this, to me, is the most fascinating aspect of the cosmos: that it keeps surprising us. The imagination of nature is far greater than the imagination of humans. In my own work, every day I am surprised if I am not surprised.
That is why we have to keep on probing with our experiments. If we merely theorized or speculated, it is most likely we would wander off on the wrong road. Our experiments keep us on the right track, and they keep us honest. We try to follow a path laid out by nature, but the markers are hidden in advance, and the destination is not always clear.
There are a host of speculations about this ultimate state of black hole collapse and its physical manifestations, with perhaps the most optimistic being that one can pass through the singularity into another universe of space and time. But until we have a theory of gravity that remains valid at the extremes of curvature and the infinitesimal scales of space and time present near the singularity of a black hole, it all remains speculation.
If time itself begins, then nothing precedes the emergence of existence and the dynamics of our world, and there appears to be no proximate cause of our very existence, or at least no natural cause. Not surprisingly, this has led some to fall back on a last refuge that allows them to avoid the truly difficult questions, namely God. But for the rest of us, dealing with a possible true beginning of time forces us to confront a series of challenges for physics.
Nature is the way it is, however, whether we like it or not, and whether time travel is possible will not be determined by whether it causes paradoxes that bother us.
As a result, while it was impossible to say that no part of the observed signal was due to inflation, it was also impossible to say with certainty that any part was. And, as Carl Sagan was fond of saying, extraordinary claims require extraordinary evidence.
In this way, without ever being able to directly detect the existence of other causally disconnected spaces outside our observable universe, we could nevertheless develop strong indirect evidence of their existence, turning metaphysics into physics. Having only indirect evidence is a less than satisfactory way of accepting new realities, but it has a noble tradition in science. Consider atoms.
The ultimate evidence for the existence of a multiverse and gravity as a quantum theory may depend as much on luck as on scientific developments. Until then, both of these concepts must be considered just strongly motivated possibilities rather than empirically validated realities.
String theory remains a fascinating area of study in mathematical physics, but whether it has anything to do with the real world remains an open question.
Let me say at the outset that I found and still find the details of the proposal ugly, and I would bet good money that its content has nothing to do with reality. But aside from my doubts, it does open the romantic possibility that right under our noses could be a portal into huge extra dimensions, large enough not only to fit Narnia, but to fit whole new universes with exotic physics, and maybe galaxies and civilizations that we can never connect with. It is not in the least sense likely, but what remains surprising to me is that it is also not impossible.
Sound crazy? I think it probably is. But sometimes crazy ideas are true. Just not very often...
But, yet again, nature doesn't exist to please us, so like it or not, it may be true.