On Tue, 04 Jun 13, Jos Bergervoet wrote:
3) Since in general we know that matter is responsible
for gravity, we assume the cause must be some form
of matter
Personally I think step 3) might be a weak point..

Precisely, if A causes B, and we have B, it does not therefore follow
that we have A. After all, something else may also cause B.

Also, we have no idea how matter generates the gravity. Does matter
create the gravity, or is it a conduit? If a conduit, then there can
be other conduits.

If gravity is a new kind of dimension, then matter is a mere
convenience, and "dark matter" nothing more than brane tension of the
gravity dimension.

The concept of "dark matter" should be an aid, not an encumbrance.
Too many astronomers chasing figments, IMO.

Eric