Dear Neil,
"OTOH, people feel a need to rove beyond a stricter approach to reality, since they just can't empirically find all they want to, with means available."
That is recognized as the case. There will continue to be empirical discoveries that will further present opportunities to understand more. However, the process of understanding begins also at the beginning. My point is that introducing guesses that are made for the purpose of filling in blanks in physics equations is not a safe practice. While it is possible for one to make a good guess, that is very unlikely if the guess is made due to ignorance about how to proceed. This practice is fertile ground for theoretical guesses. It is not fertile ground for learning the nature of the universe. I stress this point with regard to the decision to make mass an indefinable property, joining with the naturally indefinable properties of length and time, actually duration. I argue, though I have not done so here, that fundamental unity is self evident. I have found that it is not generally obvious. Yet the universe obviously operates in an orderly manner. The self evident conclusion is that the universe is fundamentally unified. There is no meaninglessness in the universe. We don't know how the universe came into being or how it continues to operate in this orderly manner, that would involve knowing what cause is. No one knows what cause is. Cause is not a part of physics equations, although it is often spoken of as if it is a part of physics equations. Even though we do not know what cause is, we can conclude why the universe exists. It must exist for the purpose of producing its effects. The most impressive effect is human free will. My last essay Lead With Innate Knowledge dealt with what physics knowledge tells us about how we learn. Pattern recognition is key. In the case of f=ma, I argue that it is pattern recognition in empirical evidence that is key. We should rely as far as we can upon that which pattern recognition is communicating to us. What f/m=a communicates to us is that the if one understands that fundamental unity must exist, then the self evident way to proceed is to consider that the ratio of the units of f and m must reduce to those of acceleration. This conclusion is 'obviously' empirically supported. Acceleration is the empirical evidence. When physics chose to not follow this lead, it was choosing to introduce fundamental disunity into physics equations.
"My own essay involved theoretically extrapolating physics to spaces with various number of dimensions, since after all we cannot do experiments in such universes. Yet I concluded at the end, that exercise doesn't prove what "really exists" beyond our world, since it is ultimately just a demonstration (altho I'm proud of that) that a class of mathematical models (if other than three spatial dimensions) would not be consistent.
"Re your solution to the problem: I am not sure how clear reliance on defining in terms of fundamentals and observable behavior etc. would change the working physics that is mostly in actual use. I presume you expect the same experimental outcomes for electromagnetic experiments that conventional theory predicts. If the satisfaction of knowing he or she is doing things the right way in principle is important to a person, well then that justifies the attitude. It reminds me of those in quantum mechanics who do not think it necessary to elaborate on "what is really there" and we should just find ways to provisionally represent for the sake of calculations. I hope I got your point, because I think the "perspective" is the important thing, not any particular physical outcome you are predicting?"
The equation f=ma worked before it was decided to make either force or mass an indefinable property. The equation is the result of pattern recognition. The equations doesn't stop working because theorists introduced the indefinable units of kilograms into the equation. The definition E=fd will work even though it carries the fundamental unity that comes along with f. Yet that fundamental disunity must reveal itself somewhere. It does so in the cases of electric charge and temperature. That is why they are both indefinable properties. That is why they cannot be defined to this day by theoretical physicists.
In a very prominent physics forum, I once said that temperature is the rate of exchange of energy between molecules. I wasn't asked to explain why I thought so. I was penalized, some silly demerit type of penalty, immediately. Further discussion led to my being banned for life. Now this is the point of bringing this experience into this message: The current status of temperature as an indefinable property continues because physicists do not know what temperature is. The demerit occurred because physicists think they know what temperature is. They think it is something other than what I described. This behavior by theoretical physicists is one example of the damage done to the learning process as a result of allowing empirically unsupportable guesses to become established parts of physics equations. Continuing in that manner prevents physics from modeling that which the empirical evidenced has to teach us. It rather sends theoretical physics spinning off into unscientific, meaning having no means of establishing empirical support, speculation.
James
