How do we know all electrons are the same?

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Discussion Overview

The discussion revolves around the question of whether all electrons are identical, exploring the implications of this idea in the context of physics, metaphysics, and particle theory. Participants examine the characteristics of electrons, the assumptions made in physics, and the consequences of differing electron properties.

Discussion Character

  • Debate/contested
  • Conceptual clarification
  • Exploratory

Main Points Raised

  • Some participants argue that the assertion that all electrons are identical is based on the lack of evidence for differences, suggesting it is an article of faith supported by Occam's razor.
  • Others propose that the inability to prove the non-existence of different mass electrons leads to a reliance on the simplicity of physical laws.
  • A participant suggests that the question of electron identity may be metaphysical in nature.
  • It is noted that electrons are defined as identical within the human-made model of reality, but this is contingent on the precision of measurements.
  • One participant points out that the treatment of identical versus non-identical particles in thermodynamics and quantum mechanics implies that if electrons were not identical, observable differences would manifest in the periodic table.
  • Another participant raises a hypothetical scenario where differing types of electrons would alter the application of the Pauli Exclusion Principle, affecting atomic structure and chemical properties.
  • A humorous anecdote is shared, arguing that electrons cannot be identical due to their distinct positions and velocities in different locations.

Areas of Agreement / Disagreement

Participants express a range of views, with no consensus reached on the identity of electrons. Some support the idea of identical electrons based on experimental evidence, while others challenge this notion from philosophical and theoretical perspectives.

Contextual Notes

Limitations include the reliance on current measurement technologies and the assumptions inherent in the definitions of particles within physics. The discussion highlights the complexity of distinguishing between theoretical models and empirical observations.

omayer
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Today I was reading for my Modern Physics class and something I read struck me in a way. The author claimed that all electrons are identical; they have the same measured mass, electric charge and magnetic dipole moment. This statement bothers me, and I haven't been able to stop thinking about it. So I come to you for some closure.

How do we know that all electrons are the same?

I understand that electrons are measured to have the same characteristics, but without infinitely precise measurements we can only be sure to a certain degree.
 
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True, it's more an article of 'faith' that Occam's razor works - with no evidence that electrons differ we assume they are the same just because the universe would be annoyingly complex if they were different.
 
We can never prove that something (like a different mass eletron) doesn't exist.

I suppose particle physics tells us that all fits into a nice grid. If electrons were different we would have to abandon the nice symmetrical model. But usually scientists are successful in assuming that laws of physics should be nice and simple at its core.
 
I think the question of “are electrons identical” is a metaphysical question.
 
Electrons are the same per definition. They are part of human made model of reality. And this model says they are the same.
but without infinitely precise measurements we can only be sure to a certain degree.
How is this different from anything in physics?
 
We can only be sure of anything to a certain degree. We haven't observed an electron with different mass, charge, magnetic dipole moment, etc. in thousands of experiments carried out in the last few centuries, which all obey the known laws of physics. We have no reason to believe that electrons with different properties exist. Are you asking out of curiosity about the merits of this statement, or because you see a reason why some electrons should be different?
 
I am going to take a different direction. Both thermodynamics and quantum mechanics treat identical particles differently from non-identical particles. If there were two kinds of electrons, that were otherwise very similar in properties (so similar that we can't tell with today's technologies) we'd still know this from the periodic table - helium would be a fairly reactive metal and oxygen would be an inert monatomic gas.

Since this is not what we observe, we can draw the inescapable conclusion.
 
Vanadium 50 said:
... we'd still know this from the periodic table ...
Vanadium raised a very good point here. The Pauli Exclusion principle explains why the periodic table is the way it is and explains why elements discovered since 1929 fit in this scheme. If all electrons were not indistinguishable, would the exclusion principle still apply?
 
I protest; electrons cannot be identical. I once found an electron in stairwell at 5th and Broadway. Some moments later there was another two floors down. They could not have been identical, but distinct. They differed in position. Not only that, the first was moving a tad bit faster.
 
  • #10
Thank you Vanadium, this is the kind of thinking I am looking for.

Vanadium 50 said:
helium would be a fairly reactive metal and oxygen would be an inert monatomic gas

Could you go into some detail about how you arrived at this. I'm afraid I do not know very much on the subject.
 
  • #11
Because there would be no Pauli exclusion principle between "Type A" and "Type B" electrons, atomic orbitals can hold twice as many electrons. So, helium, instead of having a full shell, would have a half-full shell.

My description Oxygen includes a mistake. Today it has a full shell + one shell that's missing two electrons. (2+6). It would instead have a full shell + a half full shell and would have chemical properties more similar to carbon. The inert gas would have an atomic number of 4+16 or 20, so it would be calcium.

The noble gasses would be beryllium, calcium, and halfnium.
 
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