The vastness of the universe, the incredible scale of time, the unthinkable complexity of the cell, it’s almost too much to comprehend. Indeed, it is too much to think about in a readily understandable way. Sure, astronomers have come to understand the most cosmic of scales and biologists have courageously explored the amazingly tangled interactions of the cell, but thinking in this way does not come easily to us. What is to blame? Why can’t we use our adapted brains to explore and understand these extreme scales, as we do with phenomena roughly on a human-sized scale? We need to look to the underpinnings of human cognition: our evolutionary history.

The scale of the universe simultaneously confounds our middle-world brains and gives us a sense of wonder, arising from the challenge to our brain’s evolutionary history.

Our ancestors lived in a “middle-world.” The objects and interactions that they had to worry about were middle-sized, moving at a middle-speed, changing in middle-time. For example, imagine proto-humans occupying the plains of Africa eons ago. A significant evolutionary pressure exists to be able to hunt prey consistently and successfully. There is no need to worry about microbes or planets in this scenario, just an ancient gazelle, roughly our size, bounding along at roughly our speed, over a moderate time period, and across a landscape with distances we can judge. Over time, our dealings with this middle-world were evolutionarily successful, and have carried over into today.
As we now struggle to deal with the interactions of planets, black holes, microbes, and viruses, our evolutionary history reveals itself. There was simply no pressure to adapt to life on these scales. Instead, our perceptions have been naturally selected for what was best suited to our survival: planning, judging, and reasoning about a middle-world.


Our perception of a middle-world is partly the reason why staring up at the night sky can be so evocative, or why looking into a microscope and seeing life can be so moving. Outside of our middle-world, human cognition is clutching at straws. The idea that there is a planet out there, an order of magnitude larger than our own, trillions and trillions of miles away, is fundamentally awe-inspiring. But we don’t have to travel outside our own blue marble to experience this. Witnessing a vast and beautiful landscape atop a mountain ridge is almost “spiritual,” it goes beyond the familiar sense of the middle-world and into something immediately and intensely gripping. As science pushes the boundaries of our senses, and challenge the scales, speeds, and sizes that we are adapted to, we bump up against the evolutionary history of our brains.

This is how science generates a fulfilling sense of wonder about the world. We can be always hoping for the next insight to contend with our representation of the middle-world. It changes our perspective, and illuminates a wider reality. We cannot escape our evolutionary history, but we can understand it and use it to instill passion in ourselves (however unknowingly). Never stop challenging your perceptions.

Cross-posted at the There Are Four Lights blog