Galileo was quite controversial, in part, because he argued that Earth moved around the sun, despite people’s senses deluding them that the world was static. Evolution may have primed us to see the world in terms of payoffs rather than absolute reality — this has actually helped us survive. Those who win payoffs are more likely to pass on their genes, which encode these strategies to get to the “next level” of life. It’s important to listen to people’s objections because they may bring something to your attention outside your ken. Learn from them to make your ideas sharper.
Donald Hoffman is professor of cognitive science at the University of California, Irvine. His writing has appeared in Scientific American and Edge, and his work has been featured in the Atlantic, Wired, and Quanta. He resides in Irvine, California.
DONALD HOFFMAN: Galileo was quite controversial, of course, in his time, because he was claiming that something that we all could see with our own eyes wasn’t true. We could all see that the earth doesn’t move and that the sun, and moon, and stars go around the earth. And we believed that as a race for about 2,000 years. And Galileo was saying that your eyes are lying to you. The earth actually moves and it’s not the center of the universe.
And he was put under house arrest for it. And we don’t like to be told that our senses aren’t telling us the truth. And then Galileo took it another step. He said, it’s not just that our senses are lying about movement of the earth, he said that he thought that tastes, odors, colors, and so on reside in consciousness. Hence, if the living creature were removed, all these properties, these qualities, would be utterly annihilated. That’s almost a direct quote in the translation.
So he was saying that 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. And by objective reality in this case, I’m going to use that term in a very specific way. 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. So the standard story, for example, is that the moon existed before there was any life on Earth and, perhaps, before there was any life in the universe. But it still existed.
Its existence does not depend on the perceptions of any creatures. And so that’s the sense in which I’ll talk about objective reality. And what Galileo was saying was that 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. And so I’ll talk about real experiences. So 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.
So Galileo was quite brave and quite out of the box in his thinking by saying not only the earth in his movement, but even colors, tastes, and odors are our perceptual constructions. But he wouldn’t go the next step. He wouldn’t say that shapes, and mass, and velocities of objects, and space, and time themselves are our constructions. He thought that those were objectively real. So the shape of the moon, the position of the moon, is an objectively real thing, including its mass and its velocities. So, this is a distinction that was later called the primary and secondary qualities of distinction by John Locke. Primary qualities are things like position, mass, shape, and so forth. These are presumed to exist even if no creature observes them. Whereas colors, and odors, and tastes are secondary qualities that are sort of mostly the contribution of our senses.
And in brief, what I’m saying is we need to take the next step beyond what Galileo said. It’s not just tastes, odors, and colors that are the fabrications of our senses and are not objectively real. It’s, rather, that space-time itself and everything within space-time– objects, the sun, the moon, the electrons, quarks, their shapes, if objects have shapes, their masses, their velocities– all of these physical properties are also our constructions. And I’ve come to that conclusion. It was a bit of a shock to me. We always as…
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