Imagine this. It’s winter 1862 and you’re a chemistry professor in Belgium. You’re working on one of the most pressing problems in chemistry: the structure of Benzene. Benzene is a smelly and highly flammable hydrocarbon molecule. All hydrocarbons are made of... you guessed it, hydrogen and carbon. But in benzene the ratio of these elements is a little weird. Instead of having more hydrogen atoms than carbon atoms, like most hydrocarbons, benzene has the same number of hydrogen and carbon atoms: 6 and 6. What strange molecular structure could let these atoms fit together?

Frustrated, you turn your chair towards the warm fire and take a nap. As you sleep, visions of atoms and molecules dance in your mind’s eye. They turn into a series of snakes. Then, suddenly, one of the snakes coils around and bites its tail like the ancient symbol of the ouroboros.

You’ve solved the chemical structure of benzene… in a dream! Precisely as a chemist did in 1862, completely changing the future of organic chemistry in the process, a contribution to science that earned him recognition. And it all happened while he was asleep. Thanks to... a dream?

It makes you wonder: Why do we dream?

August Kekule’s dream discovery of benzene’s molecular shape is one of history’s most famous dreams. But for most of us, dreaming is about more than making chemistry discoveries. Humans have been trying to figure out why we dream for thousands of years, probably as far back as we’ve been asking questions. And since it’s an experience we only have while we’re asleep, it’s a particularly tough question to answer.

Going back to ancient philosophers like Plato and Zhu Xi, great minds have speculated about the function and meaning of dreams. But it’s only been in the last few decades that scientific experiments have started to show us what benefits our nocturnal narratives could have.

Scientists think dreams might have many functions that influence our success, our smarts, and even our survival. We each spend about two hours dreaming every night. Over an 80-year lifetime, that’s almost 60,000 hours, or the same as ten years of waking life! Dreaming clearly must have some benefit – otherwise we wouldn’t spend so much time doing it.

Almost half of us remember at least one dream a week, and women are more likely to remember their dreams daily compared to men. There are a number of phases the brain goes through during sleep; these phases are repeated in cycles throughout the night. In the first phase, we transition from wakefulness into sleep, as we begin to relax and our breathing slows. As our body temperature drops and our breathing slows down even more, we enter light sleep. After that, we enter the deep sleep phase characterized by a particular pattern in our brain called delta waves. After that, we start the REM or "rapid eye movement" sleep stage. Our breathing gets faster, and our eyes move all over. During REM is when dreaming happens. And throughout this phase, our brain is very active - almost as active as when we are awake.

Almost all other animals... sleep. And many also experience REM sleep. So scientists think that many of these animals also dream - including your cat or dog. Probably about chasing that delicious, juicy, red ball.

The way we think about dreams has changed a lot throughout history. In most cultures around the world, dreaming has held spiritual significance. There are even dream interpretations in the Bible. But there was nowhere where decoding dreams was more popular than in ancient Egypt. The Egyptians created volumes of books full of common dreams and their supposed meanings. Professional dream interpreters used these books to help people figure out what their dreams meant.

Dreamer: I had a dream my leg came off!

Interpreter: Dreams about leg amputation symbolize a significant change or loss in one's life, often related to mobility or stability. It may represent a fear of losing control or independence. The dream could also suggest the need for resilience and adaptability in the face of challenges.

In conclusion, dreaming is a fascinating phenomenon with a long history of intrigue and interpretation. While its exact purpose and function are still under scientific investigation, dreams continue to captivate our curiosity and provide glimpses into the mysterious workings of the human mind during sleep.