Against Realism: Examining the Meaning of Local Realism

[DrChinese]

DrChinese

We lost a couple of the last posts---

could you repost your answer about the photons and electrons?

I'll come as close as I can. The question was whether photons are assumed in most posts about Bell's Theorem & entanglement.

Bell's Theorem itself used spin 1/2 electrons as the base example. But because photons are much easier to prepare, and because the resultant tests also can control for the locality assumption as well, photons are almost always used in experiments. I would say that most posts assume the discussion is about photons and spin. Technically, entanglement can be seen with other observables besides spin.

 

[rewebster]

Well, I've thought about what I see could be problems; and, it is that it was first created as a thought experiment, right? It seems a lot of physics experiments do start that way. To me, the electrons probably wouldn't react in the experiment as a simple 'electron' as so much energy would have to be pumped into them, right?; and the testing in that way may make the experiment 'different'.

And as far as photons, does the test lean toward them being waves or particles? Does it matter? And since photons are still in the 'what is it?, a wave or a particle?', it makes the testing (with the filters) a little bit removed to, as least for me, to give any weight to the results.

The results of any tests, for me, have to be taken with a grain of salt. I like wondering how many assumptions are made, first, to bias the results.

 

[AnssiH]

now, how do you relate all this to physics and 'realism' in physics?

Well the stuff about phenomenal self was just additional words to hopefully drive home how meaningful it really is to assume such a worldview where there does not actually exist any "fundamental entities". And if you can do that, it obviously does have an effect to questions about realism. Like I said early on in this thread, any form of semantical understanding (i.e. any human understanding) is at the end of the day "naive realism" in the sense that it must posit some fundamentals, and what we posit will always be - to an extent - arbitrary.

But still we keep forgetting this, and this is evident all over the place, including in the comment that Einstein made about reality of electrons, that "particle must have spin, location and so forth even when it is not being measured". He should have noticed our idea of electron exists due to certain ways we measure certain systems, and due to us imagining there really are such things as electrons causing the effects we measure.

I'll just copy-paste from my first post to this thread (#33):
Like Einstein noted himself; our comprehension of reality is based on certain assumptions about reality... ...But here he is making certain assumptions about the metaphysical identity of things. A realist doesn't have to assume that an electron has spin, a location and so on before being measured, because we can only measure things with pieces of matter, and thus these properties of electron, indeed the whole electron as we think of it, can be a result of interaction between the measurement device and something else that is not measurable as it is by matter.
(This touches little bit your above post too)

This doesn't mean we should assume our mind creates the illusion of electrons & reallity in idealistic fashion. It means we should not assume electron to be "real object" any more than a rainbow is "real object". Neither exists objectively "as they are observed" without the observer. The rainbow, as it is observed as a band of colours, is a result of interference on the observer, and it never could exist "independently".* There's no reason why electron, and everything, could not be like that. And in fact we should expect them to be like that. It's all just darwinism in extended sense.

Granted, with understanding QM there is the added complication of "semantical time"... :I

* If this doesn't seem to ring true, try to really pin down what is the location of a rainbow in an objective sense. The rainbow is certainly "real" in that everyone observe it, but can we say it is something that has independently got the properties that we measure? Like its spectrum and intensity and location? We can define rainbow in many different semantical ways, and say, for example, that it exists in the eye of the observer (where we can say what is its "real spectrum"), but then we don't account for other parts of the system that cause the pattern of rainbow (light and water droplets).

We could insist rainbow is a "real object", like we insist photons and electrons are real things, but if you assume this, your scientific explanation of the rainbow would have to include multiple dimensions where there exists multiple rainbows while we observe only one at a time. (Much like some people like to explain QM with many-worlds)

But it seems that the key to understand the reality of a rainbow or the reality of an electron is to perform such a paradigm shift where all the observed properties are just semantical properties of semantical things, and they are actually caused in part by the measurement device, and do not exist independently at all.

 

[rewebster]

1. What does realism mean to you? & 2. Einstein said:..

It depends. If you mean the 'physics' definition, or more toward 'the idea of what is real'?---When you even look around the web, there are various definitions by various people of the physics definition; and it seems every discipline (philosophy, math, etc.) uses the term 'realism'. 'Realism' to me is what appears real and logical --the moon will be there, even if I'm not looking at it. However, I don't think anyone will convince me that if one of a paired electron if rotated, that its 'other' one of the pair will rotate a light year away, or even a foot away. My logic will be different than anyone else's logic--it's based on what I have come to believe. MWI is not logical to me, and neither is time travel.


3. In your opinion, is "realism" an assumption of Bell's Theorem? If so, where does it arise?

To me, it is an assumption based on an assumption.