Sunday, 22 May 2011

Gardening with Julian Barbour 21.5.11

On the 21st of May, the group visited Julian Barbour, quantum physicist, at his home in the north of Oxfordshire.

We dove into various spaces of investigation on the nature of time and features of gravity while working with him in his delightful garden.


The End of Time, is one of the books in the Time Capsules and Conditions of Now reader which was posted to participants before the start of the physical encounters.

Barbour defines: "In The End of Time, which is written both for the popular-science market and for scientists and philosophers, I argue that the apparent passage of time is an illusion. If we could stand outside the universe and ‘see it as it is’, it would appear to be static. I arrive at this radical conclusion by considering the most basic structure of Einstein’s general theory of relativity and quantum mechanics. These are the two fundamental theories of physics, and both have been confirmed to exceptional accuracy within their respective domains of validity: large-scale phenomena for Einstein’s theory, microscopic phenomena for quantum mechanics. They have, however, remarkably different structures. In particular, time is treated in completely different ways in the two theories. This presents a severe problem, since all serious workers in the field are convinced that the two theories must eventually be subsumed in a single over-arching theory. This will be the quantum theory of the universe (also called quantum gravity). The finding of this theory presents many great difficulties, of which the ‘problem of time’ is perhaps the most severe. It seems that a choice has to be made between two irreconcilable notions of time. I argue that the only satisfactory solution is to abolish time altogether. I outline a timeless quantum theory of the universe. This includes a proposed solution to one of the most intractable problems of physics: what is the origin of the so-called arrow of time? Why is it that all phenomena distinguish a common direction of time (i.e., why does entropy increase?) but the equations of physics are symmetric with respect to the direction of time? The equations of physics allow not only the shattering of a cup that is dropped on the floor but also the re-assembly of the pieces. However, that is never observed. I believe that a theory of the universe should explain why entropy increases. In The End of Time, I suggest that a fundamental asymmetry in the space of all the possible structures of the universe could provide a basis for the arrow of time."