J.L.Lemke On-line Office

 Index to 'Across the Scales of  Time'

The Adiabatic Principle

There is a fundamental principle in physics, found in slightly different forms in mechanics, thermodynamics, and quantum theory, and generally known as the adiabatic principle. Its basic use in physics is to simplify complex analyses by justifying the neglect of certain possible (but hard to calculate) interactions as being almost certainly too small to make a noticeable difference in the final answer (the adiabatic approximation). ‘Adiabatic’ basically means ‘it doesn’t get through’ referring to energy, fields, or information. In its most basic form it is a statement about energy transfer, and it says that it takes time for energy to be transferred from one system to another; therefore the faster something happens, the less energy is transferred. This means, in effect, that a very fast and a relatively much slower process cannot efficiently communicate with one another, cannot transfer energy. This is the basic warrant for the buffering or filtering effect between non-adjacent levels in the timescale hierarchy, and therefore for the usefulness of defining timescales as being distinct from one another in the first place. 

A process which produces change only very slowly seems to us not to be a process at all, but a constant fact of life. Very slow changes do not produce ‘differences that make a difference’ (Bateson 1972) to us; they do not matter to human life. Weather change processes make a big difference to us, but climate change processes are so slow as to be irrelevant (normally, but that may be changing!). The continents are moving, the Earth’s magnetic poles are shifting, the equinoxes are precessing, the rotation of the earth is slowing, the energy output of the sun is changing -- but not fast enough to matter to our sense of geography or day and night. 

Or consider very fast processes, much faster than those at our nominal one-second focal level. If you run fast enough across the hot beachsand your feet get less burned because less total energy is transferred to you in the shorter time (for hot coals you may need additional help.) The extreme case was graphically illustrated in a recent film of H.G. Wells’ classic The Time Machine, in which the protagonist survives a nuclear blast in London by accelerating through time at the maximum rate, thus spending too little time in the actual moments of blast energy for very much of it to transfer to him and the machine. Closer to home, fast molecular and atomic processes within the human body do not play a role in our much slower biochemistry, nor can we decipher speech presented to us more rapidly than the maximum rate at which our neurons can respond and process the signals. Moreover, and this goes beyond and adds to the separability of timescales guaranteed by the adiabatic principle, we are buffered from fast, small-scale events, like ionization of individual atoms in our bodies or even errors in gene transcription, by longer term regulatory and self-correcting processes typical of the intermediate scales of autopoietic or self-organizing systems. 

Of course our small degree of autonomy from the environment, within and without, at smaller scales and larger ones, has its distinct limits. One molecular error in one cell can sometimes lead to a cancer that kills the organism. Someday we may cross a threshold in long-term climate change processes and find sudden droughts and famines on a very human timescale. The adiabatic principle has exceptions, and one of these is fundamental to human social organization.