The Dreams of Ancient Humans

Reconstruction of an elderly Neanderthal man

Source: Neanderthal-Museum, Mettmann / Wikipedia Commons / CC BY-SA 4.0

For most of our history as a species, we lived as tribal hunter-gatherers. Modern humans have been around for roughly 200,000 years, but agriculture, that is, farming, arose only 12,000 years ago. According to some estimates, we humans have lived as tribal, hunter-gatherers for over 94% of our existence. During that time, before farming, we were quite busy trying to obtain enough calories to power our large bodies (the human body is on the large side in the Animal Kingdom) and to sustain our enormous brains, which alone consume 20% of our daily calories. Food was scarce. Many berries and fruits, and the occasional spoils of a hunt, were needed to pay the high caloric demands of our body. There was no reading (not till circa 5,000 years ago), and very little time for any reflection. There were other priorities, and it was these priorities for which our brain evolved. The blueprint for our brain, encoded in our DNA, continues to be for these priorities and not for something such as reading.

Back then, humans perceived a ripe banana as a real object, out there in a real world. It was only something that should be eaten. The object was perceived as a yellow crescent, about one inch in diameter. It is unlikely that an ancient human thought that the yellow of the object and the pleasant taste of it were products of sophisticated perceptual systems, the visual apparatus and olfactory system, respectively. It is unlikely that such a human thought that there was any “information processing” involved when detecting the banana. All there was was a banana. There was no “information processing.”

The ancient humans believed that the way the world is perceived is simply the way the world is. Thus, they were “direct realists,” who believe that what we perceive is the way that the world actually is, independent of any mental representations, mental images, or sense data. There was nothing “mental” about the banana. Our brain was (is) designed for us to be direct realists and for us not to spend time worrying about how the banana is perceived nor why it is desired. The aim is to find and eat the yellow banana and not the green one.

Today, thanks to advances in science and philosophy, we know that we perceive things as they are because of sophisticated processing in the brain. These percepts are an achievement of the brain and its 120 billion neurons. Sure, there are objects out there, but they are not exactly how they seem to us. They seem to be one way or another because of how our brain “represents” these objects. Regarding taste, sugar = “good” while hydrogen peroxide = “bad.” A good example is heat. Thanks to advancements in science, we know that heat is simply molecular motion. The more motion, the more heat. This is the kinetic theory of heat. But no one experiences heat as motion, in the same way that no one experiences the color blue as simply being a higher frequency than that of red. (In physics, the difference between red and blue is simply a quantitative one, involving frequency; for us, the difference is qualitative—and somewhat inexplicable.) Bananas are tasty only to brains. Its flavor is a representation, created by a brain, that leads an animal to eat more of it and to select it over, say, green bananas or sulfur.

I often think about the everyday experience of that ancient human. During the day, he or she had little clue that the objects and terrains that were perceived were perceived as such, with their myriad colors and sounds, thanks to a brain and its sophisticated processes. But then I think of another thing. At night, something magical happened, something that could have challenged the beliefs of this human and could have challenged the belief in direct realism: dreaming. The eyes are closed, one is lying in bed, but one is experiencing (somehow) a whole reality, full of colors, objects, discussions, and desires. I wonder how this ancient human reacted to having experienced a dream. I wonder what he or she thought about dreams. Did it challenge at all his or her direct realism? Would it have offered a clue about the biological basis of our everyday experiences?