For historical reasons, I understand that a proton's charge was assigned the label of "positive", the electron's charge was assigned the label of negative, and, crucially, equations of current in E & M are written with the notion that current is the flow of positive charge despite the rarity of actual flows of protons in real systems (which I understand are mostly biological systems).

If the possibility existed to instantaneously and at no cost, retcon these associations such that protons have a negative charge, electrons have a positive charge, and current remains the flow of positive charge, would there be any beneficial or detrimental outcomes?

For instance, would there be:

  • new interpretations of physical laws that would provide different or better insights into any relevant subfield of Physics
  • significant simplifications to notation in any field of Physics or Engineering
  • significant increases in understanding in the fields of electricity, electronics, electrical engineering, radiation/radiative transport, etc.
  • a noticeably easier learning curve for any subfield of physics dealing with the concept of charge

Additionally, is there a permutation of positive charge, negative charge, and flow of current definition that would improve upon the one I suggested?

  • $\begingroup$ Two things only have two permutations. $\endgroup$ – G. Smith Jul 2 '19 at 4:19
  • $\begingroup$ Current can be defined to flow in two different directions (flow of + charge or flow of - charge). Additionally, protons can be + or -, with electrons correspondingly being - or +. Combining the two definitions of current with two different charge label permutations gives you 4 permutations. $\endgroup$ – UniqueWorldline Jul 2 '19 at 4:23
  • $\begingroup$ OK, I see what you mean. $\endgroup$ – G. Smith Jul 2 '19 at 4:27
  • $\begingroup$ While not explicitly stated, there might be some other way to recast charge and charge flow that at the very least may be "clever" in the abstract, but not very useful in most cases. Such an example, if it exists, would also be of interest. $\endgroup$ – UniqueWorldline Jul 2 '19 at 4:30
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    $\begingroup$ In a way it is like "asking if black was called white and white black would there be any change in the mathematics of color?". Definitions are like semantics, it does not make a difference to mathematics and thus to physics models. It might make a difference for beginners or lay persons who get confused with usual current direction and charge definition. $\endgroup$ – anna v Jul 2 '19 at 4:40

Electromagnetism say that there are 2 possibilities for the property of a particle which we call electric charge, physicists in the past called these 2 possibilities positive electric charge and negative electric charge. Then electromagnetism say that particles with different charges actract while particles with equal charges repel. In nature we observe that proton and electron actract each other through electric force, so physicists said that proton has positive charge and electron negative one and this is a convention. Since a convention is a choice of something that doesn't change the laws of physics you can even exchange the two charge, nothing will change. For example in nature we observe another fundamental force which is called strong force and holds together nucleons in the atom. With the strong force is associated another type of charge which physicists called colour. The property which we call colour charge has 3 possibilities, in this case the chosen convention was to call these possibilities Red, Blue and Green.


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