Schrödinger’s cat is a thought experiment designed to point out the silliness of over-interpreting quantum mechanics. It was devised in 1935. Alas: the silliness remains
This Atlantic article was published back in April but it has come to my attention only recently. Two friends have independently sent it to me in the last month and asked for my thoughts.
It’s an interview with Donald Hoffman, a professor of cognitive science at the University of California. It’s about consciousness and how to approach it as a scientific problem.
Parts of the article make sense. For example, Hoffman argues that quantum mechanics cannot be overlooked in any scientific explanation of consciousness. Quantum mechanics is the physics of tiny things — molecules and atoms and nuclei and quarks — and it is completely different from the circuits-and-pulleys stuff that most neuroscience majors learn in introductory physics. It is counterintuitive and very hard to get used to. And it doesn’t seem like much of a stretch to say that the large-scale activity of a system as complex as the human brain may depend on things that happen on the quantum scale.
But man is this article annoying. It’s a textbook example of a genre of scientific-ish writing that should have a name but I can’t think of a suitable one at the moment.
This genre is distinguished by three marks. First is its premise, which is expressed nicely in the article’s title: “The Case Against Reality.” Under this title are statements like, “The world presented to us by our perceptions is nothing like reality,” and, in Hoffman’s words, “snakes and trains have no objective features.” The point seems to be that, since the world we perceive, including snakes and trains, is composed of tiny quantum particles, and since tiny quantum particles obey laws that are alien to our senses, then the world as we know it is an illusion. It is the quantum version of a uniquely modern gotcha: “What you know is completely wrong.”
This genre’s second feature is a super genius explaining why what you know is completely wrong. But invariably the explanation only thickens the fog. Both of my friends who shared the article with me are college-educated and quite intelligent, but even they couldn’t make sense of it.
The third, and really vexing, mark of the genre (my how it needs a name) is that what it says is true-ish, usually in a narrow, reductive sense. For example, a table seems like a simple thing until you start asking questions about it. And those questions don’t end — they lead you down a molecular-optical-quantum-subnuclear hole that assuredly has no bottom. The more questions you answer, the more new questions appear. And the new questions and their answers get stranger and less intuitive and more abstract as you go. Trying to get a handle on reality in this way is not possible because it’s always slipping between your fingers (btw the Buddhists have known this for thousands of years).
Hoffman uses as an example a square blue file icon on your computer desktop. He says that the specifics of what we sense — small, square, blue — have no connection to the underlying reality, which is a zillion transistors set in a specific pattern on some chip deep in the computer’s guts. The square blue icon stands in for a reality we don’t have time to worry about. It helps us get through the day — survive, in a Darwinian sense — and that’s all it does. In the same way, Hoffman says, our perception of snakes and trains (and tables) has no clear connection to the underlying nature of these things. Our perceptions are merely symbolic. So he seems to say.
But at what level do things stop getting symbolic and start getting “real”? At what point down the hole do you say, “This is it. This is reality”? What does “real” even look like? How would we recognize it? What is an atom or a proton or a quark? Do we know these things better than we know tables? Why would we pick the molecular or atomic or nuclear or subnuclear level over any other? And why not go the other way? Physics on superbig scales is also different from our everyday physics (see general relativity, dark energy).
What really grates is the easy moral: There is no reality. “The idea that what we’re measuring are publicly accessible objects, the idea that objectivity results from the fact that you and I can measure the same object in the exact same situation and get the same results — it’s very clear from quantum mechanics that that idea has to go,” Hoffman says. But no sober physicist would talk this way about anything but individual electrons or nuclei or atoms. Or maybe tiny groups of them. They would never say that a snake or a train or a table is not a publicly accessible object. The physicist would tell us that the rules change at larger scales. They become less prone to statistics and quantum uncertainty. They get more, well, “publicly accessible.”
Make no mistake: quantum mechanics is wonderful and exciting and mind-bending stuff. It offers lessons worth learning. It is hard to teach or even talk about without losing one’s composure. But: snakes and trains have no objective features? Let’s not lose our senses as well.