The Boltzmann Brain Paradox | Clockwork of the Universe #2

Are you positive everything around you exists and isn’t just a figment of your imagination? “Of course I am” — you’ll probably say, but many generations of cosmologists weren’t so sure. Let’s dive into the Boltzmann brain paradox.

Ludwig Boltzmann was a 19th century physicist, it was a time when scientists were intensely debating whether the universe existed for a finite or infinite amount of time. We owe him many insights but the one we’re interested in today concerns entropy.

Entropy is a measure of the disorder of a system. A glass figurine your best friend gave you for your birthday is an ordered system and when it falls from your desk and shatters it becomes a disordered system. The second law of thermodynamics states that closed systems tend towards disorder: you won’t see that figurine coming back together. Boltzmann asked himself why is it so and came to the conclusion that a system evolves to a more disordered state because it’s more likely. However — that doesn’t mean it’s impossible for it to go the other way, just incredibly unlikely and thus we unfortunately will never see that figurine whole again.

But, if the universe exists for an infinite amount of time, even highly unlikely events will eventually happen, including complex objects forming randomly. That is one of many theories behind the Big Bang — all particles just “deciding” to come together in one spot. But riddle me this: what is more likely, a whole universe forming or just a brain? Using Ockham’s razor we can easily deduce it’s the latter option — about 8 octillion atoms to form a human brain is far more likely to amass than who knows how many in the whole universe.

That leaves us with the conclusion that all of our existence might be a lie, and most of us don’t like the bitter feeling this brings. But cheer up! While there’s no way to disprove this hypothesis, the same goes for proving it, so there’s really no point worrying too much about it, it’s just something to ponder while you brew the next cup of coffee. What are your thoughts on this topic? Comment below!

See you next time! Ta-ta〜