Radical Doubt Without a Head

A weird experimental post about solipsism and skepticism

This is a weird experimental post.

The last half is a soliloquy on solipsism. I originally wrote it for a work presentation (my team has a weird culture).

Why share a soliloquy? Because sometimes the best way to get into a different mindset isn't by explicit argumentation. Sometimes you just need the proper steeping.

In philosophy, solipsism is a form of radical skepticism. It's skepticism towards other minds—all I know is my conscious experience, so how can I know another person has conscious experiences like mine? Even more extreme, the solipsist claims all that really exists is their own experiences. They never come into contact with the external world directly. All one can really know is our own perceptions.

Solipsism isn't a position many (if any) people actually hold. But thinking about it and figuring out how to respond to it has a long and rich history. Most famously, Descartes started his Meditations on First Philosophy with "radical doubt", questioning everything. He found the one thing he could not doubt was his own existence: "I think, therefore I am."

Descartes, of course, tries to rebuild his other beliefs from there, but he starts by breaking himself down to the solipsist position.

I'm no solipsist, but I think taking on this view of radical doubt is mind-expanding. We only have access to our own experiences. We infer everything else.

I infer there is an external world outside my mind. I see other people having similar physical reactions to me when I have a feeling, and infer that they also have a mind and experiences. But these are inferences. We can doubt inferences.

Coming at it from a different angle, I think there is some sense that there aren't other minds like mine. I don't believe there are separable conscious experiences that can be taken from one brain and put into another. I think they are so intimately tied to the brain that when I have a conscious experience, it’s necessarily a private, unique experience. To give you that exact experience, I would need you to have the exact same cognitive machinery as me, but that cognitive machinery is what makes me me. So the only person who can be conscious exactly the way I can is me.

In my naturalistic worldview, I need to accept that objects in the external world do not directly cause my visual perceptions. It's electromagnetic radiation bouncing off of clusters of atoms in complex arrangements, coming into contact with specialized cells in my retina that fire electrical pulses in response. The world isn't simply "there" for me to experience. I only detect it through complex sensing mechanisms, and I only know about these sensing mechanisms through inference from the information they give me.

It's one thing to acknowledge that we lack certainty about other minds and the external world. It's another to get yourself into the mind-space of taking these doubts seriously. I think it's another to really adopt the viewpoint and try it on. As Paul Churchland points out in Scientific Realism and the Plasticity of Mind, we all know the Earth goes around the sun, but when we look up at the sky, we don't really know how what we're seeing relates to that model of the solar system. We don't experience the Copernican system, it's just a brute fact. 

Churchland gives instructions to undergo the Gestalt shift of seeing the structure of the solar system as it really is. It involves gazing at the night sky and tilting your head in line with the elliptical orbits of the planets. He says "a vertiginous feeling will signal success."

Here, I want to try something similar, but with solipsism. We might vaguely acknowledge that all we have are our own experiences, but adopting this mindset is a useful way of challenging us to think about how we experience the world and what we really know.

What follows is a short piece I wrote, a riff off of On Having No Head by D. E. Harding. It isn't an argument, but is meant to get you in the mindset of solipsism, to try it on, to break the patterns of thinking and engage more deeply with what it is we really know. 

I hope it works, or that you at least find it amusing.

You'll know I was successful if you get a vertiginous feeling.

Photo by Mika Ruusunen on Unsplash

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There are two types of people in the world.

One type has a head on its shoulders. They wander about the world, acting in ways sometimes predictable, sometimes not. They speak when others speak to them, navigate around objects, consume food, and engage in elaborate social rituals with others.

I am the second type of person—in fact, the only one I have ever encountered. Instead of a head, when I look at my body, I find shoulders terminating upwards into a void. That void where my head should be is simultaneously the entire world. I too speak when others speak to me, navigate the world, eat food, and socialize with others. But there is a fundamental difference. When I engage in these acts, there is something it is like to engage in them. That void that is the universe fills with sights, sounds, feelings.

Often people of the first type, those with heads, will claim to see things. They describe the colors of objects. I smile and nod, accepting their euphemisms. What they mean, of course, is that a certain wavelength of light has excited the photoreceptor cells in their retina, gone through processing in their visual cortex, resulting in a range of behaviors—including their speech act of claiming to see a color. But there is no sensation, no quality of what that experience was. This isn't anything like when I see—truly see—a color. The experience, sensation, the qualitative parts of the sight fill the void-that-is-the-universe. These can't be captured by the actions one takes, like stepping on the gas pedal because the wavelength labeled "green" has been detected coming from a traffic light.

When they are pricked or pinched by something, people with heads react by jumping back, avoiding whatever caused them bodily harm. They say it hurt, but that can't be what they really mean. The universe-where-my-head-is remains unfilled, or at least unfilled by the sensation of pain. When I stub my toe, the universe is full of pain.

Descartes famously declared: "I think, therefore I am". Descartes, as far as I can tell, had a head. His writings, however clever, were the work of millions of neurons firing together to excite muscles in his arms and hands, an amazing clockwork automaton creating pages and pages of writings.

When I dig deeper, I realize his writings have truth for me, if not for him or anyone else. I could be wrong about anything, the world could be an illusion, but the one thing I cannot doubt is my own existence, for if I did not exist, there would be no one to perceive the illusion, and no one to do the doubting.

But everything else is doubtable, and I have no good reason to think that these feelings I have, the pressure on my fingertips, the sound of the wind, or the patterns of colors that form into objects, are actually out there in the world somehow external to myself. All that I have direct access to are my experiences.

Maybe nothing but my sensations exist, and these unfeeling zombies I think I share a world with are nothing but patterns of sensations elaborated into an imagined external world apart from the universe that sits on top of my shoulders.

Perhaps, then, there is truly only one type of person, and it's unclear whether there is a world he is in or not.