Do we create reality with our mind?

[This is a transcript.]

Do we create reality with our minds? I got this question on twitter the other day and after rolling my eyes about it for some while, I decided it’s actually a good question. You might think the answer is obviously “no”. But it’s not that simple. Let me explain.

To some extent the question whether we create reality is a matter of semantics, so we have to get this out of the way first. If we *define reality to be that which is independent of our mind, then of course we don’t create it with our minds because then it wouldn’t be independent, would it.

The quip that reality is what doesn’t go away if you stop believing in it therefore should better not be used as a definition of reality, it’s rather a way of summarizing what we mean. Because if you define something to have a certain property, then it becomes moot to ask whether it has that property. It’d be like asking if red apples are red. To make sense of the question whether we create reality, we will therefore use the word “reality” to refer to what people think it means. Yes, that’s vague, and that’s why physicists normally leave that question to philosophers, but this physicist doesn’t want to leave philosophers all the fun.

The biggest problem with reality is that you can’t know that there is anything which exists without you. Because to find out you’d have to stop existing and check if it’s still there and that’s not the kind of experiment that people like to volunteer for. Strictly speaking, therefore, the only thing that you can be sure exists is yourself. This is the origin of Descartes’ “I think therefore I am”, but of everything else I can’t be quite sure. It’s also the inspiration for movies like the Matrix where an alternate reality is created by inputting it directly into people’s brain, and sometimes I think this really explains a lot.

It's called the problem of solipsism, that the only information you have to work with is the information that comes into your brain. It tells us that even if there was such a thing as reality, your brain input might not represent it, so then how are you to know what’s real? One could now debate how you know that your brain is real. I mean maybe that whole brain idea is just a marketing scheme by the education industry. Then again, the question wasn’t really about the brain but about our “mind,” so I’ll leave it to you to figure out if you want to believe that you actually do have a brain.

This video turns out to be somewhat weirder than anticipated.

To come back to the original question, the solipsism problem means you can’t know whether you do or don’t create reality with your mind. So maybe *you are the reason this video exists. It’s not that you have trouble understanding me, you don’t understand yourself.

That said, solipsism is not a widely spread philosophy for the simple reason that it has no practical consequences. While I strictly speaking can’t rule out the possibility that everything I experience is created by me, most of this so-called reality doesn’t seem to care much about what I want to create. Even if reality isn’t independent of us, it sure well does a good job pretending it is, which is how we deal with it.

The issue becomes somewhat more complicated if we take into account quantum mechanics. The reason is that the mathematical formalism of quantum mechanics contains possibilities which we never observe. The best-known example is Erwin Schrödinger’s dead-and-alive cat. These possibilities are there in the maths, but when we make an observation, they disappear. When we look at a cat, it’s either dead or alive but not both. But just exactly what is it that makes the dead-and-alive possibility of a cat disappear?

In the early days of quantum mechanics, some physicists argued that quantum mechanics gives a special role to the observer. In some sense, they thought, it seems to be the observer who makes things real. However, as physicists understood quantum mechanics increasingly well, they saw that what removes these weird mathematical possibilities is not the observation by a conscious being, it’s the use of a measurement apparatus.

Just exactly what it is that makes one thing a measurement apparatus and another thing not is still not entirely clear. That’s the famous measurement problem of quantum mechanics. But what’s clear is that it doesn’t require a mind of any sort.

Except, of course if there wasn’t a mind of some sort looking at the measurement result then we wouldn’t be talking about it being real would we. So it’s arguably the case that whenever we talk about or think about a measurement result, there must have been an observer involved, at the very least we ourself. And like with the solipsism problem, it’s impossible to rule out that this played a role. Then again, we know experimentally that to predict the outcome of an experiment we don’t need to worry about conscious observers. It just doesn’t play any role in the mathematics.

So like with the solipsism problem, we can strictly speaking not rule out that the observer influences the creation of reality in quantum mechanics. However, like with the solipsism problem, we also find that if there is such an influence, then no one can do anything with it, so for all practical purposes we might as well ignore the possibility.

In summary, do we create reality with our minds? We can strictly speaking not rule it out, but we’re pretty sure it’s a practically useless idea.