Science and the Limits of Human Comprehension
Given the size of the human brain and the cognitive limitations observed in other animals, it’s reasonable to conjecture that the human mind isn’t capable of framing and comprehending all that is. Placing the discussion in the context of an observation by John Locke, this essay posits how this conjecture is supported by scientific evidence, and it considers the conjecture’s importance for the human spirit and the broader scientific endeavor.
The mature human brain weighs a mere three pounds. And we might ask ourselves: is it up to the challenge of knowing everything?
To underscore the point, consider dogs. Dogs form complex relationships with humans and other animals, and they’re capable of learning a long list of verbal commands. But they don’t understand concepts as basic as the number ten. Hold up ten fingers in front of a dog and the canine mind withers to the task. It’s not that the dog mind recognizes the digits as “something” but doesn’t know what to do with that something. The dog mind simply isn’t wired to wrap itself around the concept. For the dog, the number ten is beyond comprehension. Yet for humans, the concept is so real, so basic, we take it for granted.
Given that such cognitive limitations can be found in every animal we observe, without exception, it seems reasonable to conjecture that, as animals, we humans share similar limitations—that there are physical realities beyond our comprehension.
John Locke raised the issue in the opening of An Essay Concerning Human Understanding, where he also addressed its relevance for intellectual inquiry.
It is of great use for the sailor to know the length of his line, though he cannot with it fathom all the depths of the ocean. (Locke, 1690)
So how might we assess the length of the sailor’s line—the limits of human comprehension? We obviously can’t comprehend what we can’t comprehend. But we might be able to see shadows of the incomprehensible in the form of inexplicable realities. And here science provides ample evidence.
Perhaps nowhere do we find more inexplicable realities than in the world of physics. The most well-known relate to wave/particle duality, the fact that photons, electrons, and even much larger entities sometimes behave like waves and sometimes like particles. This is impossible given our understanding of waves and particles in the macro world, since particles and waves are entirely different things. Yet, run one experiment and it scientifically validates the particle nature of matter. Run another, and it validates the wave nature. And things get much stranger. Niels Bohr and Albert Einstein argued for decades about Bohr’s belief that the act of observing a wave/particle caused it to collapse from a wave into a particle. Richard Feynman famously quipped that it was safe to assume no one understood quantum mechanics.
As yet another example, consider human life. Fifteen gallons of water. A gallon and a half of graphite. A gallon of frozen nitrogen. Just a handful of a few other ingredients and we have what we need to make a 150 pound human. How do all these lifeless ingredients give rise to life, and in particular, to consciousness? For all the research activity surrounding the human brain, this question in particular remains a conundrum, and it’s unlikely it will ever be resolved.
Yet, while it seems our minds are not able to “fathom all the depths of the ocean,” why might an awareness of this be “of great use”?
To understand why, consider a 2014 survey of philosophers asking if they believed in human free will. Nearly three-quarters of the respondents said they did not, at least not as most people think of free will. (Bourget and Chalmers, 2014)
The common argument derives from materialism. If a table of billiard balls is set in motion, we can in concept determine exactly where those balls will be at every instant in the future. This is because the universe operates according to physical laws. The atoms that make up our bodies are like the billiard balls goes the argument. Once set in motion, they interact according to deterministic physical laws. Our actions are simply a result of the laws of physics deterministically playing themselves out. We feel like we have free will, but we don’t. Sam Harris puts it succinctly, writing “free will is an illusion.” (Harris, 2012)
The argument is undeniably cogent, but it raises its own set of issues. For one, it takes a very simple precept, “atoms interact according to deterministic physical laws like billiard balls on a table,” and extrapolates to the very complex organisms we call humans. Given that we don’t understand how elementary collections of protons, neutrons and electrons can give rise to conscious life to begin with, is such an extrapolation warranted? Or might there be answers beyond our ability to comprehend them?
It’s not difficult to find examples where extrapolation leads to trouble. Every child knows that 1 + 2 + 3 is the same as 3 + 2 + 1. It doesn’t matter how the pennies get into the pot, we always get the same number of pennies. This is decidedly not true, however, when summing together an infinite collection of numbers, as mathematicians discovered when troubling inconsistencies arose by assuming so. For example, using arithmetical procedures that are perfectly valid for finite summations, it can be shown that 1 + 2 + 3 + 4 + 5 + … equals negative one-twelfth.
The human brain is astonishing. We need only look at the scientific and technological world we’ve created to appreciate what remarkable creatures we are. Yet, given the limited size of our brains, it stretches credulity to imagine the human mind is capable of framing and comprehending all that is. It’s something the scientifically minded need to remain keenly aware of when evaluating scientific theories, especially when such theories erode the human spirit.
This essay is based on a recent book by the author, Beyond Comprehension: A Scientific Look at the Challenge of Knowing Everything, Hamilton-Haverbrook, August 2017.
To underscore the point, consider dogs. Dogs form complex relationships with humans and other animals, and they’re capable of learning a long list of verbal commands. But they don’t understand concepts as basic as the number ten. Hold up ten fingers in front of a dog and the canine mind withers to the task. It’s not that the dog mind recognizes the digits as “something” but doesn’t know what to do with that something. The dog mind simply isn’t wired to wrap itself around the concept. For the dog, the number ten is beyond comprehension. Yet for humans, the concept is so real, so basic, we take it for granted.
Given that such cognitive limitations can be found in every animal we observe, without exception, it seems reasonable to conjecture that, as animals, we humans share similar limitations—that there are physical realities beyond our comprehension.
John Locke raised the issue in the opening of An Essay Concerning Human Understanding, where he also addressed its relevance for intellectual inquiry.
It is of great use for the sailor to know the length of his line, though he cannot with it fathom all the depths of the ocean. (Locke, 1690)
So how might we assess the length of the sailor’s line—the limits of human comprehension? We obviously can’t comprehend what we can’t comprehend. But we might be able to see shadows of the incomprehensible in the form of inexplicable realities. And here science provides ample evidence.
Perhaps nowhere do we find more inexplicable realities than in the world of physics. The most well-known relate to wave/particle duality, the fact that photons, electrons, and even much larger entities sometimes behave like waves and sometimes like particles. This is impossible given our understanding of waves and particles in the macro world, since particles and waves are entirely different things. Yet, run one experiment and it scientifically validates the particle nature of matter. Run another, and it validates the wave nature. And things get much stranger. Niels Bohr and Albert Einstein argued for decades about Bohr’s belief that the act of observing a wave/particle caused it to collapse from a wave into a particle. Richard Feynman famously quipped that it was safe to assume no one understood quantum mechanics.
As yet another example, consider human life. Fifteen gallons of water. A gallon and a half of graphite. A gallon of frozen nitrogen. Just a handful of a few other ingredients and we have what we need to make a 150 pound human. How do all these lifeless ingredients give rise to life, and in particular, to consciousness? For all the research activity surrounding the human brain, this question in particular remains a conundrum, and it’s unlikely it will ever be resolved.
Yet, while it seems our minds are not able to “fathom all the depths of the ocean,” why might an awareness of this be “of great use”?
To understand why, consider a 2014 survey of philosophers asking if they believed in human free will. Nearly three-quarters of the respondents said they did not, at least not as most people think of free will. (Bourget and Chalmers, 2014)
The common argument derives from materialism. If a table of billiard balls is set in motion, we can in concept determine exactly where those balls will be at every instant in the future. This is because the universe operates according to physical laws. The atoms that make up our bodies are like the billiard balls goes the argument. Once set in motion, they interact according to deterministic physical laws. Our actions are simply a result of the laws of physics deterministically playing themselves out. We feel like we have free will, but we don’t. Sam Harris puts it succinctly, writing “free will is an illusion.” (Harris, 2012)
The argument is undeniably cogent, but it raises its own set of issues. For one, it takes a very simple precept, “atoms interact according to deterministic physical laws like billiard balls on a table,” and extrapolates to the very complex organisms we call humans. Given that we don’t understand how elementary collections of protons, neutrons and electrons can give rise to conscious life to begin with, is such an extrapolation warranted? Or might there be answers beyond our ability to comprehend them?
It’s not difficult to find examples where extrapolation leads to trouble. Every child knows that 1 + 2 + 3 is the same as 3 + 2 + 1. It doesn’t matter how the pennies get into the pot, we always get the same number of pennies. This is decidedly not true, however, when summing together an infinite collection of numbers, as mathematicians discovered when troubling inconsistencies arose by assuming so. For example, using arithmetical procedures that are perfectly valid for finite summations, it can be shown that 1 + 2 + 3 + 4 + 5 + … equals negative one-twelfth.
The human brain is astonishing. We need only look at the scientific and technological world we’ve created to appreciate what remarkable creatures we are. Yet, given the limited size of our brains, it stretches credulity to imagine the human mind is capable of framing and comprehending all that is. It’s something the scientifically minded need to remain keenly aware of when evaluating scientific theories, especially when such theories erode the human spirit.
This essay is based on a recent book by the author, Beyond Comprehension: A Scientific Look at the Challenge of Knowing Everything, Hamilton-Haverbrook, August 2017.
- Bourget, David and David Chalmers. 2014. “What Do Philosophers Believe?” Philosophical Studies, 170 (3): pp. 465-500.
- Harris, Sam. 2012. Free Will. Washington D.C.: Free Press.
- Locke, John. An Essay Concerning Human Understanding, Volume 1, Books 1 and 2 (Project Gutenberg, 1690), http://www.gutenberg.org/ebooks/10615, Introduction, Section 7, Occasion of this Essay.
