Thanks!!! John and John; i.e. Denker and Mallinckrodt. Most excellent
summaries!
Real progress has been made, important clarifications and sharpening of
arguements.
I hope John Denker, perhaps in collusion with Mallinckrodt, will rewrite the
summary in light of the discussions of the summary.
I'm tempted to say there is a 4th camp, the one I resided in at the
beginning of the discussion and have now left.
This is the strict or strong, weight is "what the scale" says camp. In this
camp the weight of the object changes when you immerse it in water. I have
left this camp to join Mallinckrodt's camp 2 (Denker's definition 2).
I think there are three sub-camps in camp 2.
sub-camp (a): the strict version of what Denker's #2; i.e. exactly what he
said, weight depends on reference frame chosen to analyze the problem;
notice this does *not* necessarily mean the frame of a scale used to weigh
an object.
sub-camp (b) which Mallinkrodt called camp 3 and as has been noted is really
a subset of camp 2; He referred to this as the "what the scale reads" camp.
I think this is misnomer; because it is not what the scale reads while
immersed in water nor is it what the scale reads on the accelerating
elevator.
sub-camp (c): I think this is where I currently reside. I'd call it the weak
form of "what the scale reads". This is Denker's definition 2, with the
added proviso that we will preferenctially chose the frame of reference to
be the frame of reference of the scale that we choose to actually measure
the "weight" of an object, even if only in a gedanken experiment. I'm not
sure if I'm splitting hairs here. But this does make the scale reading on
the accelerating elevator synonomous with the definition of weight, as well
as for the orbiting astronaught; and matches the ordinary meaning of "an
astronaught is weightless".