The entanglement of subject and object

September 14, 2023

Sir Isaac Newton thought light consisted of particles, until Thomas Young's famous "double-slit experiment", believed to have been performed in 1801, suggested that light actually took the form of waves. But this wasn't a simple case of "scientific progress", where an old idea was replaced by a new one. As the philosopher of science Karen Barad writes, further experimentation

seemed to indicate that light manifests particle-like characteristics under one set of experimental conditions and wavelike characteristics under other circumstances. Wave-particle duality seemed to be a feature of both light and matter, [which] shook the very foundations of Newtonian physics. ... For [physicist] Niels Bohr, the crucial point is the fact that wave and particle behaviors are exhibited under complementary—that is, mutually exclusive—circumstances. According to Bohr, either we can find out which slit an electron goes through by using the which-path apparatus, in which case the resulting pattern will be that which characterizes particles, or we can forgo knowledge about which path the electron goes through (using the original unmodified two-slit apparatus) and obtain a wave pattern—we can’t have it both ways at once.

The implications of this don't just shake up Newtonian physics, they call into question the whole notion that science reveals some sort of objective reality. From Bohr, pictured above lecturing on the double-slit experiment, we might conclude, rather, that "facts" depend mostly on what kind of instrument we build to make our observations. And what kind of instrument we decide to build might reveal more about us than about the world.

Tangled with light

Thinking about this can quickly get wierd, especially, perhaps, in the words of a philosopher of science like Barad. She goes on:

Bohr’s argument for the indeterminable nature of measurement interactions is based on his insight that concepts are defined by the circumstances required for their measurement.

In other words, our beloved ideas and favorite theories wouldn't exist the way they do if we just perceived, and measured, the world in ways different from the ways we do. So are we actually perceiving the world objectively? Or is it more that we're always entangled with the world, participating in co-constructing a subjective experience of the world that is only just the product of us interacting with other beings and things that in strange ways have their own agency—and that all depends on what kind of instrument we happen to use to observe them?

Even wierder, the measuring instrument itself is also a thing with a kind of agency in a particular three-way tangle with the observer and with the thing being observed. Barad gets even more technical here, as the premise of an objective reality flies out the window:

What constitutes the object of observation and what constitutes the agencies of observation are determinable only on the condition that the measurement apparatus is specified. The apparatus enacts a cut delineating the object from the agencies of observation. Clearly, then, as we have noted, observations do not refer to properties of observation-independent objects (since they don’t preexist as such). Notice also that along the way we have confirmed another one of Bohr’s claims: the measurement interaction can be accounted for only if the measuring device is itself treated as an object, defying its purpose as a measuring instrument.

These quotes and others from Barad, though challenging to grasp, were nevertheless the subject of some brave discussion at our September dinner salon and workshop meeting, after we'd read a short selection from her dense book Meeting the Universe Halfway: Quantum Physics and the Entanglement of Matter and Meaning.

Now, what might all this have to do with hair?

Tangled with hair

The draft text we workshopped this month embraced the idea of the researcher's entanglement with objects, and the idea of co-constructing subjective experiential knowledge. Although Barad develops those ideas from the work of Niels Bohr and from the field of quantum physics, in this case we had three co-authors applying a "Baradian" approach to a social-science project about a physical and biological object: hair.

Hair, the authors pointed out, does many things, to the point where it might seem less like an object and more like a being with its own agency: hair can document drug use and exposure to environmental toxins, for example, and can save that information for a long time. Hair is also able to influence people's behavior, especially female hair influencing the male exercise of power, which was the jumping off point for this text.

The authors started with an image called "Cut It Out" by the Italian artist Marco Melgrati in support of Iranian women's protest. The authors then took turns writing very short science-fiction style stories, inspired by the image, that illustrated entanglement between people and hair, subject and object, physics and biology. Through the writing process, the three co-authors also became entangled in each other's perspectives, co-constructing a subjective experience of the world—which was one of the points of the approach.

The implications for how all human knowledge is produced, especially considering the wierd subjectivities that have become evident in quantum physics, left us much to ponder.

—Trevor Corson

Update

The hair text was later published! See here and below.

Resources & references

The following came up in our discussion or were relevant to the workshop texts or theme:

Image (top): Niels Bohr explaining the double slit light experiment in Iowa, 1950;  Des Moines Register, via Physics In History.

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