Last Tuesday, I attended to The Great Time Debate, an event hosted at the University of Toronto by the Centre for Inquiry Canada and the University of Toronto Secular Alliance, to listen to cosmologist Dick Bond, theoretical physicist Lee Smolin, and philosophy professor James Robert Brown discuss the nature of time. The talk, moderated by award-winning science journalist Dan Falk, took the form of a panel discussion/debate, in which each of the speakers was given 20 minutes to present their views, followed by a discussion with the moderator and questions posed by the audience.
Interesting speakers. Terrible presentation designs.
Though the debate itself was relatively tame, it was apparent that opinions on whether or not time was “real” varied across the board. As did the definitions of what it meant for something to be real. Whereas Bond and Brown argued that time was not “real” in the sense that we usually envision (i.e. the Newtonian notion of a “universal clock”), Smolin argued for the existence of time as real — though not quite in the Newtonian sense. I’ll admit that I didn’t fully understand much of what was said, but you can find a moderately detailed account of the talk via twitter (under the hashtag #timedebate).
What did I learn? The exact nature of time is not a simple question, and we still don’t quite know how it fits in to the giant tapestry of physics. This isn’t to say that we merely haven’t made any progress — merely that it’s too early to say whether you really could travel back in time to kill your own grandfather (or grandmother).
The panel of experts.
Once the panelists had finished their presentations and had answered a few questions from the moderator, the panel took questions from the audience. One particularly insightful audience member asked (something along the lines of) how it was possible to use physical inquiry to determine the nature of time, when physicals is premised on a certain notion of time. Or, in other words, if we start out assuming that time works a certain way in order to get to where we are today in physics, how can we then turn around and use that physics to find out the nature of time in a way that isn’t biased by our initial assumptions?
The panel agreed that, due to the circular (i.e. self-correcting) nature of scientific investigation, this didn’t pose a serious problem in the long run. The time available for a response was quite limited, so the panelists didn’t get to explain their answers in too much detail, but I believe it is an important question that warrants a more thorough response.
The panel’s point was that scientific inquiry could only function with a certain set of assumptions about how the world works. These assumptions might be informed by other scientific knowledge, intuition, or in theory (if not in practice) by wild guessing. The important thing is not that the original assumptions are correct, but rather whether investigation using these assumptions provides coherent results, i.e. coherent with our other beliefs, the rest of science, etc. If they are not, then the original assumptions are revised (or abandoned), much in the same way that we would abandon an unsuccessful scientific hypothesis.
A good example of this is the assumption built into Newtonian physics of absolute time and space. Simply put, these are the notions that time and space are neutral to physical events, and serve as more of a stage upon which these events occur. We now know these assumptions to be incorrect, due to this view of time and space being superseded by Einstein’s special relativity. More importantly, though, is that this original incorrect assumption was still able to yield relative scientific results in certain instances, and the transition from Newton to Einstein didn’t prove disastrous to the field of physics. What matters isn’t that the original assumption was correct; merely that it yielded correct predictions, and when a better theory (with different underlying assumptions) came along, our understanding of the universe was improved, rather than cast into doubt.
Then the question arises of how we know what the truth is, if our starting points are arbitrary. Isn’t this just a form of coherentism? To which I say, “yes”. However, that isn’t a problem insofar as science works and allows us to make testable predictions within a coherent framework, whatever that framework may be. Maybe one day, philosophers will discover a direct way to access logically certain truths about the universe, but until then, we might as well use the next best thing.