The difference between empirical and inferred properties
Beginning with a question posed by Jose P Koshy:
"I find no difference between 'mass' and 'length' as concepts. "
My words: So would you say that length resists force? Or, that energy is length times acceleration times distance, and, momentum is length times acceleration times time?
Perhaps you meant that they are equal in the sense of being physics properties; and, therefore, there is no reason to define them by different standards. This is, I think, the point made in your following statement:
"Anyway, for length and time, we use naturally 'indefinable units' as you say. Then why not for mass also? Can you clarify?"
Yes I can:
There are just two properties involved in forming empirical evidence; they are length and 'time' (I put the tick (') marks around the word time to emphasize that that word, as used in physics texts, does not refer to an actual property of time. Physics equations have always included only duration. Duration is a period in time which is measured as cycles of object activity.)
Empirical evidence is the starting point for all real physics knowledge. Both properties of length and 'time' are represented solely by their units in physics equations. Their units are meters and seconds. There is no way to define either length or 'time'; there are no properties that precede the properties of empirical evidence. All other properties are learned to exist because they are inferred to exist from the patterns observed, formed, from accumulating innumerable bits of information about changes of velocities of particles with respect to 'time'. It does, of course, remain possible to establish rules for measuring length and 'time'.
Rules for measuring are not definitions. When definitions do not exist, authors of physics textbooks do substitute rules for measurement. However, rules for measurement tell us nothing about the nature of a property. For example, the artifact that represents a kilogram of mass is just that, an artifact. It enables us to set a standard for the measurement of a kilogram of mass, but it cannot do that which empirical evidence does do. It cannot tell us what mass is.
All information needed to learn all that we will ever know about the mechanical operation of the Universe is delivered to us in the patterns of the empirical evidence described in the paragraph above. There is nothing needed to be added. Any additions, for example new properties inserted into physics equations by theoretical physicists, that are not demonstrated to exist directly from that empirical evidence, are not real. They lie outside the science of physics.
The manner in which all physics knowledge is guaranteed to be real is for all properties, that are inferred to exist from the patterns of empirical evidence, to be expressed in the same terms in which their empirical evidence is expressed. This practice is the guarantee that unreal substitutions cannot be arbitrarily inserted into physics equations. In addition to this practice, all inferred properties must have definitions that consist of mathematical statements that include only the units of the two properties of empirical evidence. In other words, a physics defined property is one of those many inferred properties who's units are defined in terms of the units of the only two pre-existing properties. Those two units are meters and seconds. Every one of the inferred to exist properties must have their units defined as some combination of meters and seconds only.
The mathematical beginning of physics is the equation f=ma. That equation is learned directly from the patterns observed to exist from information that consists of meters and seconds only. In the equation f=ma, the empirical evidence is represented by the letter 'a'. It represents acceleration of an object in the form of meters per second per second. This conclusion is learned from those innumerable very tiny bits of information. The other two letters 'f' and 'm' are the first two properties inferred to exist directly from the empirical evidence. All other inferred properties will necessarily need to be defined by combinations of the properties of 'f', 'm', and 'a'. There are four properties represented in those three letters. It is imperative for keeping physics real that both mass and force be properly defined properties. The truthfulness of all that will follow depends upon that being the case.
If either force or mass is left undefined, then something real is lost immediately. The main loss is the existence of fundamental unity. Also, if either of those properties is not defined solely from their empirical evidence, then they will have lost something of realness. For example, if mass is not defined solely in terms of a combination of the properties of empirical evidence, then it its nature cannot be revealed. Its nature is being communicated to us by its empirical evidence. If we lose direct connection with that which its empirical evidence is revealing to us, then we will not receive the revelation about the natures of the inferred properties. We will begin at the very beginning of physics by not knowing wat mass is.
It follows automatically, because of following the impartial rules of mathematics, from this loss that we will not know the natures of force, energy, and momentum. This loss does not prevent physics equations from making good predictions. Those predictions are made possible by equations that accurately mimic the patterns of empirical evidence. It is the continuation of the models of the patterns of empirical evidence that makes predictions possible. Those predictions are possible all the while that physicists do not know the natures of the inferred properties that they are working with.
Returning to the first step in establishing physics, force and mass must both be defined properties. In today's 'physics' mass is accepted as an undefined property. This is seen in the lack of definition of its units kilograms. Mass is represented in all physics equations only by its units of kilograms. Kilograms are not defined. In order for them to be defined with direct dependence upon the empirical evidence from which the property of mass is inferred to exist, they must be defined in the same terms as mass's empirical evidence is expressed. In other words, kilograms must be defined as some combination of meters and seconds only. Historically, this was not done and it remains the case today. Kilograms cannot be expressed in terms of meters and seconds. This means it is not defined in terms of meters and seconds.
That means its identity, its nature, is lost. We could have learned its nature only directly from its empirical evidence; that was not accomplished. The nature of mass floats freely with whatever someone wishes to guess about it. All other inferred properties inherit this loss of natural knowledge because we did not learn it from the empirical evidence. The nature of mass, and later the same error was made with regard to temperature, as treated in physics textbooks, is undefined meaning unexplained.
The corrective work that the above text calls for has already been cone. Both mass and temperature have been defined. Their units are defined as combinations of meters and seconds only following the lead that is provided directly by empirical evidence. The defined properties of mass and temperature have been put to wide useful work. The results exist on the Internet. Many are included here at FQXi.org. It is also very important to have the circular definition of electric charge removed. I have eliminated that circular definition. The Universal Constant Magnitude of 1.602x10-19 now belongs to a property who's physics role is made clear by empirical evidence.
James Putnam
