Out there
If a tree falls in a forest and no one is around to hear it, does it make a sound?
Yes: If humans disappeared, the sound would continue to travel through the air, and heavy objects will continue to fall from the sky. However, there would be no humans around to know it. This is the view of realism.
No: Air vibrations only become sound once our complex ear mechanism perceives them, and our nervous system subsequently processes them as information. A tree that falls will produce vibration. But without ears to hear, there will be no sound. This is the perspective of “immaterialism,” or philosophical idealism.
Perception
Realists believe that things out there in the real world are, indeed, as they appear in our minds. This idea is, of course, challenged by many. Different animals see the world differently. For example, snakes can perceive part of the infrared (IR) spectrum of light. Hence, snakes see what you and I feel as heat. The same principle applies to other senses. Dogs can hear part of the ultrasound spectrum (high-pitched frequencies) that we humans can’t. This is the basis of the ultrasonic whistle and the MP3 (or other audio compression formats). Both are built around human hearing limitations. In his famous paper “What Is It Like to Be a Bat?” philosopher Thomas Nagel used this flying mammal as an example to illustrate that our perception of the world is subjective. Bat’s sensory apparatus is radically different from ours, relying on echolocation to perceive and navigate the world. Since our perception of the world is dominated by vision, humans, and bats perceive a completely different reality. Consequently, Nagel argues that humans cannot access the bat mind.
Humans, bats, and any sentient being alike all have their limitations when it comes to perceiving the physical world. The reason, neuroscientist Anil Seth argues, is that brains did not evolve to perceive the external world as is. They didn’t evolve to use complex language, or to philosophize about these questions, either. Brains evolved to regulate internal physiology. Brains evolved to keep themselves (and their bodies) alive. The external data that we perceive doesn’t need to capture all that’s out there, only the information useful for our survival.
Perception without conception is blind.
Immanuel Kant, Critique of Pure Reason (1789)
Representation
We are limited on which aspects of reality we can perceive. But what we do perceive, the external stimuli that reach our brain through different physiological processes, is that real?
In 1781, Immanuel Kant’s idealism theory proposed that humans’ perceptions are the result of a psychological process that blends what our senses perceive with what we already know, think, feel, and believe. Like in Plato’s allegory of the cave, our experience of reality is bounded to a given representation of it. Our perception of reality is always framed by our interpretation of it. In Stumbling on Happiness, psychologist Daniel Gilbert argues (paraphrasing Piaget) that humans are born realists and, subsequently—often unconsciously—shift to idealism. For example, small children cover their faces under their blankies, thinking that because they can’t see, others can’t see them either. Only later in life, they come to realize that others might have a different perspective. Only later do we figure that those objective stimuli out there create subjective stimuli in our minds. These subjective stimuli are what frame our real world. Is the glass half full or half empty?
The magic trick
Without the brain’s filling-in trick, Gilbert argues, we would not have the subjective experiences of what we call reality. He also notes the brain tricks us also in other ways. A brain capable of filling in can also leave out. Often, the futures we imagine contain details invented by our brains and lack others that were ignored. When you imagine yourself being richer than Jeff Bezos, do you envision all the bureaucratic burden and decision-making responsibilities as well? We look for what our brain wants to see, permanently living at the edge between the outside world and an illusion, an augmented reality.
We cannot do without reality and we cannot do without illusion. Each serves a purpose, each imposes a limit on the influence of the other, and our experience of the world is the artful compromise that these tough competitors negotiate.
Daniel Gilbert, Stumbling on Happiness (2006)
Hallucinating
We are programmed to recognize specific patterns automatically. We transform various input data into information that is meaningful for us. Sometimes we see “real” objects. Often, however, we see animals in cloud formations, three-dimensional objects on bidimensional images, and we see faces, many of them. Many see the face of the virgin Mary on our wall filled with humidity stains (or a monkey Jesus). Some Earthers have seen a face on Mars. Seth wonders, is our reality just a hallucination that we all agree on? After all, we all recognize smiley and angry faces on our screens, where there are none.
What most of us call reality is a construction made of external stimuli and a pre-existing narrative of how things work. We can only perceive a portion of what’s out there. We only get to experience our personal representation of it. We may still be far from understanding what it is like to be a bat. But, can we get to experience the realities of others?
Cover image by Pexels from Pixabay.