Is reality real? These neuroscientists don’t think so | Big Think

Is there external reality? Of course there's an external reality. The world exists. It's just that we don't see it as it is. We can never see it as it is. In fact, it's even useful to not see it as it is.

And the reason is because we have no direct access to that physical world other than through our senses. And because our senses conflate multiple aspects of that world, we can never know whether our perceptions are in any way accurate. It's not so much do we see the world in the way that it really is, but do we actually even see it accurately? And the answer is no, we don't.

However paradoxical it sounds, if we think of what is visible as just what projects to the eyes, we see much more than is visible. Let me give you an example. I walk into a room, and there's graffiti on the wall, and imagine it's graffiti that I find really offensive. I look at it, I flush, my heart starts to race, I'm outraged, I'm taken aback.

Of course, if I didn't know the language in which it was written, I could have had exactly the same retinal events and the same events in my early visual system, without any corresponding reaction. Much more shows up for us than just what projects into our nervous system. Our senses are also making up the tastes, odors and colors that we experience. They're not properties of an objective reality. They're actually properties of our senses that they're fabricating.

By objective reality, I mean what most physicists would mean, and that is that something is objectively real if it would continue to exist, even if there were no creatures to perceive it. Colors, odors, tastes and so on are not real in that sense of objective reality. They are real in a different sense. They're real experiences. Your headache is a real experience, even though it could not exist without you perceiving it.

So it exists in a different way than the objective reality that physicists talk about. We always assume that our senses are telling us the truth. So it was quite a stunning shock to me when I realized that it's not just tastes, odors and colors that are the fabrications of our senses and are not objectively real. Space-time itself, and everything within space-time. Objects, electrons, corks, the sun, the moon, their shapes, their masses, their velocities, all of these physical properties are also constructions.

Sometimes it's really difficult for people to understand that the data that your brain is receiving is meaningless because when they open their eyes, they look around, they say, "Well, I see everything. What do you mean it's meaningless?" A really simple example is color. Scientific knowledge of what light is shows us that our natural perception leaves a lot on the table.

The human perception of color is limited really by the principles of quantum mechanics. It's interesting to compare the human perception of color to the perception of sound. When you have two pure tones together, like a C and a G, a simple chord, that's a fifth. If you hear that, you can hear the separate tones, even though they're played together and you hear a chord, you can also sense the separate tones.

Whereas, with colors, if you have two different colors, say spectral green and spectral red and mix them. What you see is not a chord where you can see the distinct identities preserved, but rather an intermediate color. In fact, you'll see something that looks like yellow. It's as if in music, when you play to the C and a G together, instead of hearing a chord, you just heard the note E, the intermediate note.

So at this most basic level, we don't represent even the information we're getting in any accurate way. And the reason is because it was useful to see it this way. So what are you seeing? The utility of the data, not the data. Evolution by natural selection has shaped us with perceptions that are designed to keep us alive.

So if I see a snake, don't pick it up. If I see a cliff, don't jump off. If I see a train, don't step in front of it. We have to take our perceptions seriously, but that does not entitle us to take them literally. Perception itself. A pers...