In my 2004 essay, "The Debate Over Time," I discussed the differences between two conceptions of time, a "mechanical" conception of time popular in modern science, and a "process" conception of time supported by both common sense and strong philosophical argument.  One implication of this debate is that if the process philosophers are right, science in general and relativity physics in particular have been been based on an inadequate conception of time.  I am now pleased to report that some physicists have come to the same conclusion.  The Australian physicist Reginald Cahill appears to have emerged as the leading advocate for a radically revised physics.

Cahill is attempting nothing less than a revolutionary paradigm shift in physics. It is to be accomplished by modeling time as a process instead of as a geometric line. The old geometric model captures some aspects of time, such as the notion of events in an order and the quantitative "length of time" between events, but it is unable to capture the fundamental distinction between the past and the future. "The past is fixed and at best partially recorded, while the future is undecided and certainly not recorded" (p. 12). The failure of physics to model time as a process led eventually to Einstein's conception of time as the fourth dimension of spacetime, the block universe whose future popped into existence as soon as the universe was formed, and his conception of gravity as a curvature of spacetime. Perhaps Cahill's most startling claim is that "the Einstein curved spacetime construct is without experimental support, that it actually never was confirmed by the key and celebrated experiments...," but it persists in the face of contradictory evidence because "the non-process paradigm has acquired the status of a belief system, as distinct from a science..." (10-11). Process physics does support the relativistic effects of special relativity (time-dilation and length contraction), but places them within a different theory of time, space and gravity. Cahill says that quantum effects also emerge naturally from process physics.

Process physics models reality as a "self-organizing semantic information system," whereas non-process models are merely syntactical. For example, a Turing computing machine is a syntactical system in the sense that the information held by the machine is meaningless to the machine itself. My word processor doesn't understand what I write, although hopefully I do! A syntactical system is just a set of objects acted upon by other objects, and such a system can be modeled with a set of symbols to represent the objects and a set of rules describing their interactions. As biologist Robert Rosen has written, "the formalist position, that the universe of discourse needs to consist of nothing more than meaningless symbols pushed around by definite rules of manipulation, is exactly parallel to the mechanical picture of the phenomenal world as consisting of nothing more than configurations of structureless particles, pushed around by impressed forces."

^[1] Rosen has argued that this framework is inadequate for understanding living systems, let alone human minds. Now Cahill is arguing that it is inadequate for understanding reality in general.

If one takes seriously the notion that the future is less defined than the past, then one may regard reality as a process of ongoing self-definition, with each "now" an occasion of self-definition. We need a model of an information system that can actively use the information within itself to further define itself, continually constructing its future out of its past. Thinkers in the humanities and social sciences have described human minds and cultures this way. Cahill is trying to model all of physical reality as such a semantic system. He models it mathematically as a stochastic neural network whose nodes are sub-networks of the same kind, ad infinitum (no "bottom" or beginning of reality being supposed), and whose iterations within a nonlinear dynamic process capture the notion of process time. The fundamental equation describing the matrix iterations includes a noise factor that "limits the self-referential relational information but, significantly, also acts in such a way that the network is innovative in the sense of generating semantic information...." (p. 24). So the system never stops defining itself. From this mathematical foundation, he proceeds to reformulate and extend fundamental physics, including a new theory of quantum gravity.

I am not a physicist, so I can't evaluate Cahill's physics as such. I am a sociologist interested in paradigm shifts, and I give Cahill high marks for addressing the problems with the prevailing scientific paradigm. How well his work will stand up to scientific scrutiny remains to be seen. Time (what else?) will tell.

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[1] Robert Rosen.  1991.  Life Itself: A Comprehensive Inquiry Into the Nature, Origin, and Fabrication of Life.  New York: Columbia University Press, p. 7.