by RArvay » Sun Dec 07, 2014 11:32 am
At an early age the question occurred to me, are all electrons exactly alike? The answer, according to physics, is yes. Even if you distinguish between two electrons in terms of their spin, and other quantum descriptors, every electron is identical to every other electron in terms of mass and charge. This is what it means to be a fundamental particle.
Which brings up the following question: if two separate things are exactly alike in every respect, then do they in fact have separate identities? This is more than a philosophical question. It has been seriously proposed (by Wheeler and Feynman) that there is only one electron in all the universe. If so, then all electrons are not only identical, they have literally the same identity.
While it is interesting, let us set aside that proposal for the moment, taking a skeptical view of it.
Concerning fungibility, let’s introduce an analogy by way of money. If I have two coins, let us say pennies, they are clearly separate and distinct physical objects. Even if they seem to be exactly alike in every respect, they are not. To make the analogy easier, however, let us suppose that the two pennies have different dates on them, and have other obvious physical differences. This clarifies that they are not physically identical.
If, however, I deposit the two coins into my bank account, then for financial purposes, they cease to be distinct in terms of dollars and cents. All that matters from then on is that I have two cents in my account. I can at a later time withdraw two cents with no regard for which two pennies I withdraw. They are fungible.
Likewise, electrons can be “deposited to” and “withdrawn from” an atom during chemical reactions. An atom can absorb and emit electrons repeatedly, with no distinction between the electrons. For example an atom can lose an electron and become positively ionized, and then gain an electron, returning to its neutral state, and the result is the same regardless of whether the electron that was lost is then replaced by the same or another electron.
While semantics should not confuse the issue, it is important to regard the words “identical” and “identity” as being valid in the discussion. If two objects are identical, that is, absolutely identical, then they do not have separate identities, and are therefore one and the same object. Of course, location is part of an object’s identity, but not part of its fundamental identity. (Or is it?)
Where this discussion becomes germaine to physics is in the question of the fundamental nature of the universe. Why are all electrons the same? Not all quarks are the same. Physics has mapped out the various fundamental particles, but has not explained how this scheme of things came about. Why are there six kinds of quark? Could a universe be composed of more, or fewer? For that matter, could a hypothetical universe exist in which no two electrons are alike, each one having a different mass and charge than the others?
What overarching fundamental principle of reality causes things to be as they are?
At an early age the question occurred to me, are all electrons exactly alike? The answer, according to physics, is yes. Even if you distinguish between two electrons in terms of their spin, and other quantum descriptors, every electron is identical to every other electron in terms of mass and charge. This is what it means to be a fundamental particle.
Which brings up the following question: if two separate things are exactly alike in every respect, then do they in fact have separate identities? This is more than a philosophical question. It has been seriously proposed (by Wheeler and Feynman) that there is only one electron in all the universe. If so, then all electrons are not only identical, they have literally the same identity.
While it is interesting, let us set aside that proposal for the moment, taking a skeptical view of it.
Concerning fungibility, let’s introduce an analogy by way of money. If I have two coins, let us say pennies, they are clearly separate and distinct physical objects. Even if they seem to be exactly alike in every respect, they are not. To make the analogy easier, however, let us suppose that the two pennies have different dates on them, and have other obvious physical differences. This clarifies that they are not physically identical.
If, however, I deposit the two coins into my bank account, then for financial purposes, they cease to be distinct in terms of dollars and cents. All that matters from then on is that I have two cents in my account. I can at a later time withdraw two cents with no regard for which two pennies I withdraw. They are fungible.
Likewise, electrons can be “deposited to” and “withdrawn from” an atom during chemical reactions. An atom can absorb and emit electrons repeatedly, with no distinction between the electrons. For example an atom can lose an electron and become positively ionized, and then gain an electron, returning to its neutral state, and the result is the same regardless of whether the electron that was lost is then replaced by the same or another electron.
While semantics should not confuse the issue, it is important to regard the words “identical” and “identity” as being valid in the discussion. If two objects are identical, that is, absolutely identical, then they do not have separate identities, and are therefore one and the same object. Of course, location is part of an object’s identity, but not part of its fundamental identity. (Or is it?)
Where this discussion becomes germaine to physics is in the question of the fundamental nature of the universe. Why are all electrons the same? Not all quarks are the same. Physics has mapped out the various fundamental particles, but has not explained how this scheme of things came about. Why are there six kinds of quark? Could a universe be composed of more, or fewer? For that matter, could a hypothetical universe exist in which no two electrons are alike, each one having a different mass and charge than the others?
What overarching fundamental principle of reality causes things to be as they are?
