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Assistant Professor of Psychology, Stanford University

There is an old joke about a physicist, a biologist, and an epistemologist being asked to name the most impressive invention or scientific advance of modern times. The physicist does not hesitate—"It is quantum theory. It has completely transformed the way we understand matter." The biologist says "No. It is the discovery of DNA—it has completely transformed the way we understand life." The epistemologist looks at them both and says "I think it's the thermos." The thermos? Why on earth the thermos? "Well," the epistemologist explains patiently, "If you put something cold in it, it will keep it cold. And if you put something hot in it, it will keep it hot." Yeah, so what?, everyone asks. "Aha!" the epistemologist raises a triumphant finger "How does it know?"

With this in mind, it may seem foolhardy to claim that epistemology will change the world. And yet, that is precisely what I intend to do here. I think that knowledge about how we know will change everything. By understanding the mechanisms of how humans create knowledge, we will be able to break through normal human cognitive limitations and think the previously unthinkable.

The reason the change is happening now is that modern Cognitive Science has taken the role of empirical epistemology. The empirical approach to the origins of knowledge is bringing about breathtaking breakthroughs and turning what once were age-old philosophical mysteries into mere scientific puzzles.

Let me give you an example. One of the great mysteries of the mind is how we are able to think about things we can never see or touch. How do we come to represent and reason about abstract domains like time, justice, or ideas? All of our experience with the world is physical, accomplished through sensory perception and motor action. Our eyes collect photons reflected by surfaces in the world, our ears receive air-vibrations created by physical objects, our noses and tongues collect molecules, and our skin responds to physical pressure. In turn, we are able to exert physical action on the world through motor responses, bending our knees and flexing our toes in just the right amount to defy gravity. And yet our internal mental lives go far beyond those things observable through physical experience; we invent sophisticated notions of number and time, we theorize about atoms and invisible forces, and we worry about love, justice, ideas, goals, and principles. So, how is it possible for the simple building blocks of perception and action to give rise to our ability to reason about domains like mathematics, time, justice, or ideas?

Previous approaches to this question have vexed scholars. Plato, for example, concluded that we cannot learn these things, and so we must instead recollect them from past incarnations of our souls. As silly as this answer may seem, it was the best we could do for several thousand years. And even some of our most elegant and modern theories (e.g., Chomskyan linguistics) have been awkwardly forced to conclude that highly improbable modern concepts like ‘carburetor' and ‘bureaucrat' must be coded into our genes (a small step forward from past incarnations of our souls).

But in the past ten years, research in cognitive science has started uncovering the neural and psychological substrates of abstract thought, tracing the acquisition and consolidation of information from motor movements to abstract notions like mathematics and time. These studies have discovered that human cognition, even in its most abstract and sophisticated form, is deeply embodied, deeply dependent on the processes and representations underlying perception and motor action. We invent all kinds of complex abstract ideas, but we have to do it with old hardware: machinery that evolved for moving around, eating, and mating, not for playing chess, composing symphonies, inventing particle colliders, or engaging in epistemology for that matter. Being able to re-use this old machinery for new purposes has allowed us to build tremendously rich knowledge repertoires. But it also means that the evolutionary adaptations made for basic perception and motor action have inadvertently shaped and constrained even our most sophisticated mental efforts. Understanding how our evolved machinery both helps and constrains us in creating knowledge, will allow us to create new knowledge, either by using our old mental machinery in yet new ways, or by using new and different machinery for knowledge-making, augmenting our normal cognition.

So why will knowing more about how we know change everything? Because everything in our world is based on knowledge. Humans, leaps and bounds beyond any other creatures, acquire, create, share, and pass on vast quantities of knowledge. All scientific advances, inventions, and discoveries are acts of knowledge creation. We owe civilization, culture, science, art, and technology all to our ability to acquire and create knowledge. When we study the mechanics of knowledge building, we are approaching an understanding of what it means to be human—the very nature of the human essence. Understanding the building blocks and the limitations of the normal human knowledge building mechanisms will allow us to get beyond them. And what lies beyond is, well, yet unknown...