The mind that thinks our thoughts is a pretty special place. But is it distinct from the brain? Is there, in fact, a soul directing our thoughts or are they determined entirely by the output of our biology? Could that mouse scampering through your garden be thinking deep thoughts, or are humans really special?
Before there was cognitive science, before there was neurobiology — before there was even biology — humanists have wrestled with these questions. Traditionally, philosophy of mind scholars in the West have fallen on one side or the other of the mind/body question.
Dualists would say that the mind would function just as it does whether or not it has a body. Dualists say that there is something special about the mind – it’s not just an incredibly interesting and complicated machine. Trees and tables and billiard balls can be explained by physics and biology, but you need to add something extra, some non-physical property, to explain human consciousness.
On the other side are physicalists. Most philosophers today still find the physicalist explanation more compelling: that mental phenomena have a physiological or a neurophysiological basis. Even that simple statement, though, raises more questions. For example, if physicalism is characterized as everything physical, what does “physical” mean? It can’t mean tangible, since gravity is a physical force but it can’t be touched; rather, says philosophy professor Karen Bennett, it means that “everything is accounted for, or generated by, the kinds of things physicists talk about.” Physicists might not discuss chairs very often, but chairs are fully composed of the kinds of things physics talks about, like atoms and molecules.
Philosophers address the questions we care about for which there is no specialized – typically empirical – methodology, says Derk Pereboom, Susan Linn Sage Professor in Philosophy and Ethics and Stanford H. Taylor ’50 Chair of the Sage School. In psychology, two of those questions philosophy addresses are, what’s the right model for cognition and how do we account for consciousness?
“Philosophy has an important role to play there, developing models to explain these questions,” says Pereboom.
The topic of consciousness has attracted considerable attention in recent years. It’s a familiar phenomenon, the most intimate thing we experience – that everything looks a certain way and feels a certain way to us. Yet ever since Sigmund Freud, it’s become common to believe that there’s a great deal of sub- or unconscious process going on beneath our awareness. As Pereboom notes, you might not be conscious of your anger toward your father but it’s still having an effect.
Seeing Is Believing – Not
Nicholas Silins, associate professor of philosophy, examines the mind through questions relating to perception, drawing on the fields of philosophy, vision science and the theory of probability to answer how exactly we learn from our visual experiences of the world.
“The way you see the world can directly give you evidence that the world is the way it seems,” says Silins. “Think about how, when you have a bad headache, you can go straight from your pain to a justified belief you are in pain. Contrast that with using an emissions test to form a belief about the emissions rating of a Volkswagen diesel car, where you’d need to rely on a belief that a defect device didn’t kick in during the test to rig the result.”
Against a long, skeptical tradition in philosophy, Silins defends the view that our visual experiences are like the pain, not like the emissions test: they can directly justify our beliefs about the external world without our needing to rely on further beliefs. Some of our beliefs about the external world can then legitimately be taken as foundations for further enquiry, without depending on any further beliefs themselves.
Graduate student Lu Teng’s current project studies the epistemological implications of “cognitive penetration.” She’s interested in developing a view of when perceptual experiences are and are not evidentially valuable, drawing on current psychological research.
“We tend to think that perceptual experiences tell us about what the external world is like without being influenced by our own mind,” says Teng. “However, recent empirical research indicates that that’s not true: our beliefs, expectations and other mental states can causally influence what we experience.”
But if our perception sometimes results from our prior attitudes about the world, rather than being a neutral mirror to the world, this can call into question the ability of our perceptions to justify our beliefs, says Silins. For example, while it might be a good thing for a radiologist to see more in an x-ray than a patient, it could be tragic for someone with racial bias to see a wallet as a gun.
Mind & Machine
Technological metaphors have always been used to explain the mind: John Locke described an infant’s mind as a blank slate; Freud compared the mind to hydraulic and electro-magnetic systems. The current favorite metaphor is that the mind is a computer.