Forces of nature and such

[Quid est Veritas?]

I think you are misunderstanding him.

No, I don't think I am. His whole point is that the epistemic groundwork is secure enough in physics, that the perceptual side of observation is attenuated, and on this score, he holds the philosophic reservations thereon not applicable to direct observation in physics. But again, the point here was to investigate the epistemic basis itself, as to the possibility of more fundamental forces.

Not so

They never deduced the principles you'd like them to, and they had torsion catapults. Unless you have some example I am unaware of?

Their financial system was based on a concept of "amount of gold" or "amount of silver."

Yet they had no concept of mass. I can measure out 5 apples, have I thus determined the mass of the apples? Of course not.

The clearest indication of this is that they had no universal weight. A libra of gold was a different weight (in our sense) from a libra of silver or bronze. Equivalences were drawn by value, that 10 libra of bronze equalled 1 libra of silver say, not by actual weight. They also used other measures like the modius for corn or the quinaria for water (both a measure and a pipe diameter in this case) without drawing the conclusion of a certain amount of matter being equivalent between each. The concept of mass as we understand it, as a quantity of matter, simply did not exist, and wouldn't until some point from the late empire into the mediaeval period. This concept is required to be able to assign or attribute an effect to it. The weight was an attribute of a specific substance, along with things like texture or colour, not a universal attribute of all matter. Some think this is probably why they thought a heavier object would fall quicker than a lighter object.

 

[Radagast]

The concept of mass as we understand it, as a quantity of matter, simply did not exist

It certainly did; and Archimedes used it to derive the concept of density.

 

[Quid est Veritas?]

It certainly did; and Archimedes used it to derive the concept of density.

Citation? Archimedes derived density by force, as in the Archimedes principle, not mass.

 

[Radagast]

Citation? Archimedes derived density by force, as in the Archimedes principle, not mass.

Archimedes was fully aware that the value of gold was related to the amount of gold, and that you could calculate the amount of gold in a gold-silver alloy by means of its density.

And in his On Floating Bodies, Archimedes carefully distinguishes actual mass/weight from the forces involved.

But perhaps I should ask exactly what you mean by "mass," and how you measure it without reference to some kind of force?

 

[Quid est Veritas?]

Archimedes was fully aware that the value of gold was related to the amount of gold, and that you could calculate the amount of gold in a gold-silver alloy by means of its density.

And in his On Floating Bodies, Archimedes carefully distinguishes actual mass/weight from the forces involved.

But perhaps I should ask exactly what you mean by "mass," and how you measure it without reference to some kind of force?

The ancient Greeks saw weight as an attribute of a subtance, as I said, not a universal of matter. In this case, Archimedes weighed gold and the other object on a scale until it balanced (meaning the forces equaled) then submerged the scale. If it no longer balanced, then the objects clearly did not consist of the same substance, as their buoyant force, and therefore their density, differed. The concept of mass is not required nor mentioned.

What I mean by mass is the measure of the amount of matter in a substance; which we universalise between substances, that the mass of 1 kg of iron is the same as 1 kg of gold, which the ancients simply didn't do. The concept of a universal 'matter' that can be measured, only arose under Neoplatonism later, and even Greek Atomism is about the interaction of invisible indivisible bodies and void, and there is debate on whether atoms were even thought to have weight as it seems to have been treated more as effect. They certainly weighed things, but they did not think that if things balanced on the scale, that there was a correspondence in the amounts of the substance therefore.

And in his On Floating Bodies, Archimedes carefully distinguishes actual mass/weight from the forces involved.

Could you supply the exact passage or citation, if you have it to hand?

 

[Radagast]

What I mean by mass is the measure of the amount of matter in a substance

And no doubt you measure that by counting atoms, but how do you get the mass of an atom?

but they did not think that if things balanced on the scale, that there was a correspondence in the amounts of the substance therefore.

So you keep claiming.

Could you supply the exact passage or citation, if you have it to hand?

Book I, Prop 7.

 

[Quid est Veritas?]

And no doubt you measure that by counting atoms, but how do you get the mass of an atom?

We both know weight is an important surrogate, but weight and mass are not the same, and in the Peripatetic or Ancient Atomist theories of weight, we are dealing with an attribute of each specific substance.

Book I, Prop 7.

Bodies heavier than the liquid on being let go into the liquid will move down as much might sink and will be lighter in the liquid so much as the weight of the liquid having so much volume as is the volume of the solid magnitude.

And so, it is clear that it will move downwards, as much as they might be moving down. For the downward parts of it squeeze the parts of the liquid more than parts that lie equally with them, since the solid magnitude is supposed heavier than the liquid. And that they will be lighter, as was said, will be shown. Let there be some magnitude, A, which is heavier than the liquid. And let there be a weight, BG, of the magnitude on-which-A-is, and of the liquid having a volume equal to A, namely B. One must show that magnitude A when in the liquid will have a weight equal to G. For let there be taken a certain magnitude, that-on-which-D-is, lighter than the liquid, and let the weight of the magnitude on-which-D-is be equal to weight B, but let the weight of the liquid having a volume equal to magnitude D be be equal to weight BG. In fact, when the magnitudes on-which-A, D-are are composed into the same magnitude, the magnitude of both together will be equal in weight to the liquid. For the weight of both magnitudes together is equal to both weights together BG and B, but the weight of the liquid having a volume equal to both magnitudes together is equal to the same weights. And so, when the magnitudes are let go into the liquid, they will equally-incline with the liquid and will move neither upwards nor downwards. Wherefore, the magnitude on-which-A-is will move downwards and by so much force it is being draw upwards by the magnitude on-which-D-is, but that magnitude on-which-D-is, since it is lighter than the liquid, will move upwards by so much force as is weight G. For it has been shown that solid magnitudes lighter than the liquid being forced into the liquid move upwards by so much force as is the weight by which the liquid of equal volume with the magnitude is heavier than the magnitude. But the liquid having a volume equal to D is heavier than magnitude D by weight G. And so it is clear that the magnitude on-which-A-is will also move downwards by so much weight as is G.

I don't really see how this "carefully distinguishes actual mass/weight from the forces involved".