system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: At a subatomic level, and from a physics point of view, what is charge? What is the difference between positive and negative charge?

In most explanations of charge, a positive charge or a negative charge is just the state of positive or negative particles outnumbering their counterparts. But in regards to the positive or negative particles that determine charge, what determines *their* charge?
gpt
The charge of individual particles is a fundamental property of the particle.  All fundamental particles have charges that are multiples of 1/3rd the elementary charge unit, which is the same amount of charge an electron or proton have.  Insofar as can be determined, this value never changes, attempts to change it change the particle not the charge, and all particles of the same type have the same charge.