Mr. Johnstone,
With the essay competition drawing to a close, it strikes me that a summation, or at least a punctuation, of our ongoing conversation up to this point may be in order.
Thomas S. Kuhn, in his marvelous book 'The Structure of Scientific Revolutions,' draws a distinction between what he terms "normal science" and "extraordinary science," or science in crisis, with the latter being caused by extraordinarily persistent and intractable anomalies which do not yield to resolution under an existing scientific paradigm. Kuhn writes, "When . . . an anomaly comes to seem more than just another puzzle of normal science, the transition to crisis and to extraordinary science has begun. The anomaly itself now comes to be more generally recognized as such by the profession. More and more attention is devoted to it by more and more of the field's most eminent men. If it still continues to resist, as it usually does not, many of them may come to view its resolution as *the* subject matter of their discipline." (pp.82-83, 3rd edition) Such persistent anomalies, according to Kuhn, are what may lead to scientific revolutions and paradigm changes.
If physics today is not already in such a state of crisis then it certainly is well on its way to being there. For evidence of this assertion one need only read Lee Smolin's 'The Trouble With Physics,' which includes his remarkable (and oft-quoted by me) comment, "More and more, I have the feeling that quantum theory and general relativity are both deeply wrong about the nature of time. It is not enough to combine them. There is a deeper problem, perhaps going back to the origin of physics." (page 256)
As I've often repeated here, I'm convinced that Smolin is correct in this assertion and that what is needed to break through the logjam in which physics now finds itself is a new paradigm for the fundamental nature of time. Moreover, I would wager that the needed paradigm will involve a Machian model such as has been proposed in my current FQXi essay and in reference 4 to this essay.
Thinking about time under the currently prevailing paradigm has become more and more obviously bankrupt. The euphemistically named "operational" definition of time, ("time is that which is measured by clocks") is then typically followed by, in essence, defining a clock as "that which measures time." To his credit, Brian Greene at least acknowledged this circularity when he wrote, "Of course, this shifts the burden to the definition of the word 'clock'; here we can somewhat loosely think of a clock as a device that undergoes perfectly regular cycles of motion. . . . Of course the meaning of 'perfectly regular cycles of motion' implicitly involves a notion of time, since 'regular' refers to equal time durations" (p. 34, 'The Elegant Universe')
This line of reasoning leads Greene to write elsewhere, "Just as we envision all of space as *really* being out there, as *really* existing, we should also envision all of time as *really* being out there, as *really* existing, too. Past , present, and future certainly appear to be distinct entities, But as Einstein once said, 'For we convinced physicists, the distinction between past, present, and future is only an illusion, however persistent.'" (p.139, 'The Fabric of the Cosmos')
Under the Machian paradigm of time which we have proposed and discussed in this thread the distinction between past, present, and future is most definitely *not* an illusion! Past, present, and future are synonymous with different configurations of our evolving universe. And I think that no serious scientist currently maintains that the universe is not an objective reality which evolves.
Given the statement by Lee Smolin quoted above, I can only conclude that he is primed to accept and embrace the need for an new paradigm for the fundamental nature of time, and I look forward eagerly to reading the new book which he supposedly is writing on the topic. If the book does not address some of the ideas we have been discussing here I will be greatly surprised, not to mention disappointed. As the saying goes, time will tell.
Cheers
