A decision about lambda must of course await adequate observational data.
It may indeed be zero. What I object to is the idea that any indication of a non-zero
value should be looked upon with suspicion because it _ought_ to be zero. I know & give
due weight to the usual arguments - it's more parsimonious not to have adjustable
parameters in a theory &c. The same argument tells you that the mass of the electron is
zero because the Dirac equation is more elegant that way.
> >> "What does it mean for the Universe, is more to the point? Never
> >> expansion and separation of all non-bound systems... a very lonely
> >> Universe in the distant future. All non-bound masses will disappear
> >> each other's c-boundary. Maybe. That's if the lambda factor is
> >> well-behaved. In the far future it may reverse and bring it all back
> >> a Big Crunch. There's no theoretical way of knowing what the long
> >> behaviour of lambda will be. It's a vacuum energy phenomenon and
> >> something physics still has a poor grasp on."
> > Lambda may be entirely a vacuum energy phenomenon - if you come at the
> >from a particle physicist/quantum field theorist position. If you
> approach it from
> >the geometrically-minded general relativist's position, lambda may be a
> >feature of the laws of physics - e.g., to _define_ a metric in terms of
> curvature in the
> >sort of affine theory which Schroedinger explored.
> Any Web-references for that? I'd have to dig it up from my friendly [but
> far away] University library otherwise. IMO the Universe is a rather
> perverse mix of Platonic forms and rascally matter, so geometric
> arguments may be more sirens of the mind than sure guides to truth.
I don't know any web reference. Schroedinger summarizes his work on this in the
last chapter of his _Space-Time Structure_ (Cambridge, 1963). I now doubt that this
theory is viable, but it is a counterexample to the idea that lambda could come about
only by the flawed route which it took historically.
Plato was right but
a) the "forms" need not be geometric,
b) they are contingent, &
c) clothed forms are better than naked ones - cf.Jn.1:14.
If anyone replies that "Plato was right" with these qualifications is equivalent to
"Plato was wrong", I won't argue!
George L. Murphy