Re: Cliff Parker's question

[Cliff Parker <cparker@EMPOWERING.COM>]

> [I said] If I have things right here then mass describes the amount of matter just as
> energy describes the amount of work that can be done.  If GR is correct and
> E=MC^2 (energy and mass are somehow interchangeable) then wouldn't matter and
> the ability to do work also be interchangeable?

> [Jack said]   False analogy.  Mass is to matter as energy is to ?.  Mass and energy
> are the numerical results of measurements.  Measurements on what?  Matter is
> the "what", in the case of mass.  You must be specific in stating what it is
> that you are measuring, in the case of energy.

What is non specific about stating that the ability to do work is the thing that is
being measured in the case of energy?  Is it that this "thing" is not tangible?  If so
then it seems to me that mass is no more tangible.  We can compare weights, we can
compare inertias, but we can never sense mass directly just as we can never sense the
ability to do work directly.