The issue is not settled. It is an open question in physics.
Resolutions which have been proposed, and are neatly summarised here:
http://dmoz.org/Society/Philosophy/Philosophy_of_Science/Physics/Time_and_Timelessness/
Of particular interest is article of Prof. Stenger
...
Time symmetry at the quantum level makes it possible to draw a model
of underlying reality that is simpler and more symmetric than the
conventional view. This reality is timeless, with no beginning, no
end, and no arrow of time. Observations at the smallest distances and
highest energies reveal a picture of localized, discrete material
bodies moving along definite spacetime paths in an otherwise empty
void, with no fundamental distinction between past and future and no
need to introduce "real" continuous fields. This is the picture
revealed to us by the standard model of elementary particle and
forces, which is fully consistent with all empirical data..."
http://www.colorado.edu/philosophy/vstenger/void.html
There are also some speculations that 'act of measurement' itroduces element
of irreversibility into QM. (It is the Shrodinger (or Dirac) eq. of QM which
has time-symmetry), the measurment 'theory' is sort of ad-hoc addition:
However, that also is not universally accepted and depenfs on interpretation:
http://dmoz.org/Science/Physics/Quantum_Mechanics/Interpretations/ |
