The notion of a completely objective reality is the bedrock principle of science, which is the main reason Einstein was so uncomfortable with Bohr’s “nothing exists without observation” take on quantum theory. Yet Christopher Fuchs, a physicist now at the University of Massachusetts, and Ruediger Schack of Royal Holloway University of London disagree. They contend that Bohr was on to something: Our notion of an objective reality needs modification. The physical world cannot be separated from our own efforts to probe it. How could it be otherwise, since we ourselves are embedded in the very world we’re seeking to understand?*
They call their way of looking at quantum mechanics QBism, a modified version of a theory they developed with University of New Mexico physicist Carlton Caves called Quantum Bayesianism. QBism combines quantum mechanics with Bayesian probability, a variation on standard probability in which the odds of any given event are revised as one gains more knowledge of the many possible conditions tied to the event. For example, if a patient complains of headaches to a doctor, the initial odds of a diagnosis of brain cancer might be low. As the doctor examines the patient, the odds of a cancer diagnosis may go up or down.
... QBism applies similar reasoning to physics experiments: Whenever physicists perform an experiment, they are updating their own subjective knowledge. There is no fixed underlying reality that different observers can independently experience. Just as a doctor must assess each patient individually, so too must a physicist approach the fresh, ever-changing phenomena presented by the quantum world. In QBism, the experimentalist cannot be separated from the experiment — both are immersed in the same living, unpredictable moment.
“If QBism says one radical and important thing about the nature of reality, then observer participancy is it,” says Schack. “Subjects matter. And reality, if QBism is right, cannot be conceived without always including the subject. That’s certainly a bold statement about the real world, about reality. It’s just a feature of reality that is very fundamental.”
StreetlightX — StreetlightX
In other words, if you take seriously the idea that measurements only reveal things qua measured, and there's no reason to think that it's possible to measure things qua things as they are independent of or prior to measurement, then you immediately end up in Kantianism. — Snakes Alive
’. What it seems to do is undermine the presumption of the mind- independent nature of the objects of physics — Wayfarer
There's no need to try and attempt to 'get outside' because one is 'already inside', if I may put it that way. — StreetlightX
↪Snakes Alive Measurement = physical interaction = not exclusive to humans = no Kantianism. — StreetlightX
In other words, if you take seriously the idea that measurements only reveal things qua measured, and there's no reason to think that it's possible to measure things qua things as they are independent of or prior to measurement, then you immediately end up in Kantianism. — Snakes Alive
? — StreetlightX
we are not recording what the thing is independent of that measuremen — Snakes Alive
It misunderstands what it means to be red, which is just to look like that in the presence of light. — StreetlightX
But: 'what does it look like in the absence of a look?' - this is just a badly formed question, leading to false puzzles. — StreetlightX
Very well – but if you say all properties of the thing we're interested in are relative to the measurement in this way (what it is to have that property just is to look a certain way under certain conditions), then this collapses into Kantianism. We deal with phenomena, and we learn about things only that they look certain ways to us. — Snakes Alive
But what is the status of 'us'? — StreetlightX
You're treating 'us' as an exception that is somehow different from 'everything else'; but this is just what is unwarranted. — StreetlightX
How am I doing this? — Snakes Alive
"Us" would be whoever's measuring. — Snakes Alive
This sounds like the sort of thing Stephen Hawking would say, and it is wishful thinking on the part of people that would like to co-opt science in their evangelical quest to spread reductive materialism.The notion of a completely objective reality is the bedrock principle of science
By assuming this entails Kantianism. — StreetlightX
And what is measuring? A: A physical interaction. — StreetlightX
The claim is belied by the rest of the post, in which four scientists: Planck, Bohr, Fuchs and Schack - two of them in the veritable pantheon of physicists - disagree with it. We could add Heisenberg and Bohm to that for a start. — andrewk
But if you say all properties of the thing we're interested in are relative to the measurement in this way (what it is to have that property just is to look a certain way under certain conditions), then this collapses into Kantianism — Snakes Alive
Consider modifying this bold bit to something like: 'what it is to have that property is just to be interacted with in a certain way under certain conditions". Is this a Kantianism? But there are no noumena here: the idea is that all properties are relational in this way: any interaction whatsoever will yield a 'result' appropriate to that interaction. There's only a Kantianism if one tries to substaintialize an 'object' apart from these interactions (like a 'red' without the conditions of 'red': a nonsense). There's nothing special about measurement. If there were no measurement, the universe would still be there, quite independent of it, insofar as measurement is just a subclass of physical interactions, which take place all the time, everywhere. The charge of Kantianism only holds if measurement is not understood to belong to the larger class of physical interactions - that is, if you exceptionalize measurement. But this is just what the QM shows to be false: we are no different to anything else in the universe. — StreetlightX
if one tries to substaintialize an 'object' apart from these interactions (like a 'red' without the conditions of 'red': a nonsense). — StreetlightX
If there were no measurement, the universe would still be there — StreetlightX
When we seek knowledge of things, we don't generally think of ourselves as just reporting how the measured thing affects the measurement apparatus — Snakes Alive
the universe is, you say, outside of our measuring it, but all we ascertain in measurement are our interactions with it! — Snakes Alive
Ideally this bumping tells you something about the phenomena, — StreetlightX
But this is a false dichotomy through and through. All we ascertain in measurement are our interactions with it, yes, but who gives a fuck about us? Why are we the 'measure or measure', as it were? It's only by elevating measurement itself into a transcendental principle of 'universe-constitution' that you can get the kind of idealist peddling that Wayfrer would like. But that's unwarrented, unscientific hogwash. — StreetlightX
but who gives a fuck about us? — StreetlightX
what does follow is that the only thing measurement ever allows us to partake in are those things that are ontologically dependent on it — Snakes Alive
'The only things we can measure are those things that we can measure.' — StreetlightX
I feel that Einstein eludes classification. He was undoubtedly deeply philosophical, and I think his ideas changed greatly during the course of his life, which I see as a sign of an open mind. His large collection of memorable sayings is so varied that people of all different conflicting philosophical positions like to claim him as one of their own, but I I doubt he belongs to any neatly labelled philosophical school, or maybe he belonged to many of them, one after another.What about Einstein, though? He was rather the odd man out in this respect, don’t you think? — Wayfarer
That measurement changes the object, insofar as it's being measured, means that we can't ever see something except qua measured, and so can't know what it is independently of that measurement occurring. — Snakes Alive
Reworded: Measurement changes the object, insofar as it's being measured, means that we can't ever see something except qua measured, and so... it makes no sense to speak of knowledge otherwise than this. — StreetlightX
Get involved in philosophical discussions about knowledge, truth, language, consciousness, science, politics, religion, logic and mathematics, art, history, and lots more. No ads, no clutter, and very little agreement — just fascinating conversations.