Exploring the Boundaries of Science

Here are a few more articles I’ve read recently exploring the boundaries of what science can tell us.

In case you were wondering if scientific realism was a thing that scientists themselves were unsure about, here’s a blog post (via @realscientists) by a physicist about it, which concludes as follows:

So where does this leave us? Pretty much with the concept of realism in science in tatters. The internals of models changes in unpredictable ways when science advances. Even within a given model, the internals can be changed with mathematical tricks and for some definitions of realism, experiment has largely ruled it out.  Thus we are left with our models that describe aspects of reality but should never be mistaken for reality itself. Immanuel Kant (1724 – 1804), the great German philosopher, would not be surprised.

I wouldn’t go so far to say the concept of realism in science is “in tatters,” rather that it’s not a solid assumption as many think.

Next, this article (via @EpicureanDeal) talks about a new approach to quantum mechanics that uses Bayesian methods to interpret the probabilities:

His [Christopher Fuchs’s] view arises from a relatively recent interpretation of quantum mechanics called Quantum Bayesianism, or QBism for short. It’s an approach long championed by quantum physicist Christopher Fuchs, developed with collaborators Rüdiger Schack and Carlton Caves.

Their view is that quantum theory’s conundrums stem from banishing the subject — the scientist or whoever — from the facts about “objective reality.” When a physicist calculates the odds of finding an electron in various locations, or the probability that a radioactive atom will decay today, those probabilities are generally taken as objective facts about nature. So reality is like dice. Einstein didn’t like it. Nevertheless the world respects the probabilities that quantum mechanics provides, and never defies them.

Some of the weirdness in quantum mechanics stems from the fact that it seems that observations “create” reality.

Much of the supposedly inexplicable quantum weirdness dissolves when this view is adopted, the QBists contend. When a measurement is made, for instance, multiple possibilities encompassed by the wave function all disappear, except for the one corresponding to the result of the measurement. This “collapse of the wave function” has elicited all sorts of philosophical hand-wringing about measurements “creating reality” instead of just recording it. But from the QBist perspective, a measurement is just an experience for an “agent” acting as an investigator of nature. What gets created is merely a new experience for the agent.

Any such agent can use the rules of quantum mechanics to calculate the odds for various measurement outcomes on a system described by a given quantum state. But those odds are the agent’s personal judgment. That means that the quantum state in the first place is also a personal judgment of the agent. “The notorious ‘collapse of the wave-function’ is nothing but the updating of an agent’s state assignment on the basis of her experience,” Fuchs, Mermin and Schack write.

This interpretation of quantum mechanics places the agent in the center.

To a QBist, the personal experience of an agent is the most important thing about quantum physics. Quantum states cannot be objective elements of reality because they are subjective, personal information, used by an agent for calculating the odds of future experiences.

Which I’m still trying to wrap my head around.

Lastly, another piece from Michael De Dora about philosophy and science:

Yet an increasing number of people believe philosophy is useless or obsolete, and that all our efforts should be focused on science. This is deeply problematic, mainly because whether we realize it or not, we all must engage in philosophy before we engage in any kind of science. As Daniel Dennett has said, “There is no such thing as philosophy-free science, just science that has been conducted without any consideration of its underlying philosophical assumptions.” To deny this is to oversimplify.

Philosophy deals with the base assumptions about how we interact with the world. Everything else is built on top of that.

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