Thought Experiments are not Dead, I think

Thought experiments are mental exercises that allow individuals to explore hypothetical scenarios and test their intuitions and beliefs about the world. They have been used for centuries by philosophers, scientists, and other thinkers to gain insights into various fields of study, from physics and mathematics to ethics and metaphysics.

You use them too, but probably haven’t realised it!

The most well-known thought experiment is that of Albert Einstein imagining riding on the front of a light wave when he was just 16 years old. That ultimately led along the path to his Theory of Special Relativity. But he created many other thought experiments using the approach as a fundamental tool for understanding physical issues and for explaining his concepts to others.

For special relativity, he employed moving trains and flashes of lightning to explain his most penetrating insights. For general relativity, he considered a person falling off a roof, accelerating elevators, blind beetles crawling on curved surfaces and the like.

In his debates with Niels Bohr on the nature of reality, Einstein proposed imaginary devices intended to show, at least in concept, how the Heisenberg uncertainty principle might be evaded.

In a profound contribution to the literature on quantum mechanics, Einstein considered two particles briefly interacting and then flying apart so that their states are correlated, anticipating the phenomenon known as quantum entanglement. (Wikipedia)

Recently, a thought experiment has led to the suggestion that Black holes destroy nearby quantum superpositions. That’s a deep one, and I’ll come back to it later. But as is so often the case, it led me down a rabbit hole.

History

The history of thought experiments can be traced back to ancient Greece, where philosophers such as Plato and Aristotle used them to explore philosophical concepts. For example, in his famous “Allegory of the Cave,” Plato presents a thought experiment in which a group of people are chained in a cave and only able to see shadows on a wall. He uses this scenario to explore the nature of reality and the limitations of human knowledge.

In the centuries that followed, thought experiments continued to be used by philosophers and other thinkers.

In the 17th century, for example, the French philosopher René Descartes used a thought experiment involving an evil demon to explore the nature of knowledge and reality. He suggested that it was possible that everything we perceive is an illusion created by the demon, and that the only thing we can know for sure is that we exist.

In the 20th century, thought experiments became increasingly important in the fields of physics and mathematics. I’ve already mentioned Einstein’s famous experiment, but there have been others, perhaps less well-known outside their fields.

Philosophy and ethics

In recent years, thought experiments have also been used in the field of philosophy to explore ethical and moral issues. For example, philosopher Judith Jarvis Thomson presented a thought experiment in which a person wakes up to find themselves connected to a famous violinist who needs their help to survive. She used this scenario to explore the ethics of abortion and the rights of individuals over their own bodies.

One of the most famous thought experiments in philosophy is the “trolley problem.” This scenario involves a trolley hurtling towards a group of people, and the individual faced with the decision of whether to divert the trolley onto a different track, killing one person instead of several. The trolley problem has been used to explore the ethics of utilitarianism, deontology, and other moral frameworks.

Deontological ethics or deontology is the normative ethical theory that the morality of an action should be based on whether that action itself is right or wrong under a series of rules and principles, rather than based on the consequences of the action. That’s a new one to me, and learning such stuff is one of the rewards of researching stories.

Wider scope

Thought experiments are not limited to philosophy and science, however. They can also be used in everyday life to explore personal beliefs and values. Most of us day-dream, but day-dreams are really thought experiments! For example, you might use a thought experiment to consider what you would do if you suddenly won the lottery, or were faced with a difficult moral decision such as turning off a life-support machine attached to a relative.

Criticisms

Despite their usefulness, thought experiments are not without their critics. Some argue that they are too abstract and divorced from real-world situations to be of practical use. Others suggest that they are often based on unrealistic or flawed assumptions that undermine their usefulness. To me, these criticisms seem to be worthless. We have learned so much from ‘what ifs’.

And the latest thoughts on Black Holes?

A new thought experiment suggests that the mere presence of a black hole can destroy a nearby quantum spatial superposition. Developed by physicists in the US, the experiment implies that the long-range gravitational field of the particle in the superposition will interact with the black hole’s event horizon, causing cause the quantum superposition to decohere within finite time. — Physics World

This latest thought experiment was ‘thought up’ by physicists at the University of Chicago and Princeton University and is described in a preprint on the arXiv server. Co-author Daine Danielson said that the experiment considers a hidden observer behind a black hole’s event horizon.

I was a bit puzzled as the story said:

Because real experiments cannot be done, physicists use thought experiments to try to develop a consistent theory of quantum gravity. These seek to understand the behaviour of quantum systems under extreme gravitational conditions such as those that exist at the event horizon of a black hole. This is a boundary surrounding a black hole, beyond which nothing — not even light — can escape the black hole’s immense gravitational field. This implies that information can enter a black hole, but it cannot leave. (Physics World ibid.)

I’m way past my sell-by date on cosmology and most of my thought experiments these days revolve around wondering what it’s like to be dead. Nevertheless, I was under the impression that it was accepted theory that Hawking Radiation could be emitted by a black hole.

The new thought experiment suggests that the black hole acts as an observer in the classic ‘Alice/Bob’ communication scenario and de-coheres information.

If you want to think more on this subject then check out the paper:

Conclusion

I've though a lot about this. Regardless of the criticisms, thought experiments remain an important tool for exploring philosophical and scientific concepts. They allow us to explore hypothetical scenarios and test our beliefs and intuitions about the world (and universe), and they have played a vital role in the development of many of the most important ideas in philosophy and science.

The latest thoughts on Black Holes have generated plenty of discussion, and that’s what’s good about them.

And you don’t need multi-billion dollar infrastructure either, although that too is important.

Thought experiments are accessible by anyone. Create your own today and dream on!

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This story was originally published on Medium on May 3, 2023.

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