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Science: Scientific laws

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Nobel chemist Ilya Prigogine’s work on dissipative structures, complex systems, and irreversibility, Barbara Adam argues, not only challenged particular scientific laws but the classical notion of a scientific law. In classical physics, to arrive at a law was to arrive at a timeless substructure of natural reality.

Adam summarizes the implications of Prigogine’s work:

“As long as laws continue to be conceptualised as ‘outside time and space,’ his dissipative processes cannot be thought about in a meaningful way. Once scientists think of nature as ‘T’-time-full, laws themselves come to be understood as developing; and reversibility, far from being the most fundamental aspect of nature, comes to be recognized as a product of the consciousness of the human observer.”

Two interrelated clarifications, regarding what Adam means by “T-time” and “reversibility”: Newtonian physics deals with motion in time, and ignores the changes that take place in the things that’s moving. Motion is a change relative to position, and thus can move either backward or forward. Motion is reversible, symmetrical with regard to past and future. Newtonian physics “excludes decay and ageing, the unidirectionality of energy exchange, and the asymmetry of interactions, the irreversibility of living processes and the cumulation of knowledge.” Newtonian time is not an arrow. For Newtonian dynamics, energy is neither created nor destroyed.

(Thermodynamics agrees that energy is neither created nor destroyed but goes on to say, beyond Newton, that the amount of useful energy declines. This introduces directionality into natural systems, but doesn’t quite get it. An organism may be depleted of energy usable for itself, but at the same time expending energy that can be used by another organism. So, there’s both directionality and a kind of circularity/feedback at work.)

Prigogine’s T-time, in any case, is defined over against the reversible time of Newton, time indifferent to past and future. Real events are not smoothly symmetrical as the events described in Newtonian physics. Prigogine’s model was not the machine, but non-mechanical flowing structures that generate levels of order through fluctuations and broken symmetries.

Adam writes, “the integral age of a system, which expresses both irreversible directionality, and an essential difference between past and future.” This, Prirogine argues, is not a human projection onto nature but a law of nature, a time integral to change and not merely the background against which change occurs.

More fully: “In distinction to the Newtonian t-coordinate he introduced a time operator T. He demonstrated that the broken symmetries of real events can only be described with time T rather than the t-coordinate of Newtonian and quantum physics. This T time is to be understood as analogous to historical time; as the internal age of a system which expresses irreversibilty, directionality and an essential difference between past and future.”

This changes the character of scientific laws, Adam argues, because it integrates time’s arrow into the formulation of those laws, rather than seeking structures and regularities beyond space and time.

posted by Peter J. Leithart on Thursday, June 19, 2008 at 10:56 am

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Science: Scientific laws

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