The ultimate clock is the Universe itself, which through its progressive expansion in size defines a "cosmic time." It seems as if there may be some deep significance in this — both the thermodynamic arrow of time and the philosophers' arrow of time seem to have their roots in the expansion of the Universe, in the cosmological arrow of time. …
The gravitational equations that govern the motion of the cosmos impose a restriction (known technically as a constraint) which has the effect of eliminating the time coordinate. As a result all change must be gauged by correlations. Ultimately, everything must be correlated with the size of the Universe. Any vestige of a moving present has faded completely, exactly as the B-theorists have always claimed.
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This confuses time as the dimension of the Universe along which processes unfold with the unfolding of processes from start to finish ("the arrow of time").
From the perspective of the General Theory of Relativity, interpreted in terms of Systemic Functional Linguistic Theory, the expansion of the Universe is the relative expansion of space intervals, and the relative contraction of time intervals (as between ticks of a clock).
By the same token, a process of change is distinct from the time dimension along which it unfolds. The dimension itself involves taking the unfolding of one process as a standard, such as one revolution of the Earth around the Sun, and correlating the temporal duration of that process with the durations of other processes. The size (spatial extent) of the Universe is thus largely irrelevant to such correlations.
And none of this has any bearing on a 'moving present', since the present is just a reference point on the time axis, corresponding to the time of sensing or saying (of construing experience as meaning or wording).
I wonder whether Smolin's 2013 book "From the Crisis in Physics to the Future of the Universe" offers anything more? To condense by paraphrasing:
ReplyDelete"It is the change from a quantum, indefinite present to a classical, definite past, that defines the arrow of time itself, pointing it always in the “forward” direction as the quantum present constantly churns out a classical past. We can never go back: we can’t change the past. In fact, the past no longer exists. Once something is definite, its job is done and it is gone. But the future is a quantum future: it’s a place only of possibilities, not certainties. Not everything is possible in the future, of course: only things that can emerge from the present through the laws of quantum mechanics. Like the past, it doesn’t truly exist, but for a different reason. The past is not real because its job is done and it can have no further influence on the world. The future is not real because nothing in it can be made concrete until the present reaches it. In this view, we live constantly in the moment in which probabilities are becoming actualities, in which reality – what is, what has happened and been imprinted on the world – is at the point of condensing, of changing from quantum to classical. We live at the border. But if the future is quantum, what happens to all those futures that aren’t selected by the decohering present?
Huge thanks for alerting me to this book. I've downloaded a copy and will work my way through it after Davies & Gribbin.
DeleteOn the basis of the above, from an SFL perspective, Smolin seems to be conflating the cline of instantiation with tense: the present as a point of reference on the time axis. This will be interesting to tease apart.
Chris, indeed (but Smolin does have one or two detractors in that very controversial part of physics). Of vaguely related interest, I hope to publish soon on the past–present–future in music listening, in which I incorporate the psychology of activated memory (the immediate past), entrainment (the immediate future), and "the musical now". It will present new ways of analysing music that are closer to the listener's immediate experience than previous approaches. I do even cite Halliday on the way Theme adds cohesion to a text, given that we know how the start of a perceived segment (language, number strings, etc) has privileged access from dormant memory.
ReplyDeleteI've had a quick glance at the book. My first impressions are that he is chiefly concerned with arguing for the "reality" of time. He seems to be a former Platonist who has seen the error of his ways :-)
DeleteI like his emphasis on 'relationalism' and I share his negative assessment of String Theory. For me, the problem is that it is an exploration of the mathematics of physics, rather than a mathematical description of physical phenomena.
Good luck with the publication. It looks like a very original approach. I hope it proves fruitful.
Smolin's book won't be explored on this blog. The closest he comes to defining what he means by 'time' (p xxviii) is:
ReplyDelete"Time must be a consequence of change; without alteration in the world, there can be no time. Philosophers say that time is relational — it is an aspect of relations, such as causality, that govern change."
From the perspective developed here, Smolin mistakes change for time, and so, changeless for timeless. His argument for the reality of time is actually an argument against changelessness.