Tom: "James, I realize you've created a self-consistent narrative of the physical world that suits you, and that's fine. Enjoy it. Its objective value, however, is nil. There is no way to *objectively* evaluate empirical information except by theory."
Me: The choice is invent or discover. The theoretical path is one of invention. Taking direction only from empirical evidence is one of discovery. By way of correction: "There is no way to *objectively* evaluate empirical information except by theory." should read: 'There is no way to objectively evaluate theoretical physics equations except by theory.'
Physics equation are not naturally theoretical. They are naturally empirical. An empirical physics equations is one that contains nothing other than what empirical evidence reveals to us. The evidence that this path is being successfully followed is that all properties, after the two original empirical properties of length and time, are defined properties. Their identities are formed only from the terms in which their empirical evidence is expressed.
A defined property is defined in the same terms as its empirical evidence is expressed. As a counter example, kilograms is not defined in the same terms as its empirical evidence is expressed. Kilograms is invented with no past. It came into existence abruptly when the theorists invented it. It is not expressible in any terms that came before it.
The property of mass is not expressible in terms of any property that came before it. Contrary to this there is the stark example of the opposite effort taken immediately afterwards in the case of force. Force is 'defined' in terms of mass, length, and time. Unfortunately for force and for physics, force is 'defined' using the artificially indefinable property of mass.
It can be easily judged when physics has been returned to an empirical basis. The evidence for this is that there are no indefinable properties in physics equations other than the two original properties of empirical evidence, length and time. Since properties are represented only by their units in physics equations, the direct evidence that physics equations have been returned to an empirical basis is that all units are defined units except for the units of the two original properties of empirical evidence.
The only two units that will appear naturally as fundamental indefinable units are those of length and time, presently meters and seconds. All other units appearing in physics equation will have definitions that are formed from combinations of meters and seconds only.
James Putnam
