SKEPTICISM AS A VIRTUE
Keith Parsons
Skepticism in its most extreme form is a program of universal doubt. Every knowledge claim is subjected to intense critical scrutiny and supposedly shown to be uncertain, inconclusive, unproven, dubitable, and, in general, lacking in epistemic credentials. Such skepticism is familiar from the first of Descartes's Meditations (1641).
It draws upon a number of standard arguments: the fallibility of sense perception, the dream argument, the hallucination argument, the evil demon scenario, or, more recently, the brain in a vat argument. According to this latter scenario, imagine that you were drugged and kidnapped by a mad scientist who surgically removed your brain, suspended it in a vat of liquid, and connected all of your sensory inputs to the outputs of an immensely powerful supercomputer. This supercomputer is programmed to deliver the same sensory experiences that you had before the mad surgery. That is, you experience getting up in the morning, greeting family, having breakfast, and going about your day as usual. The computer makes everything look, sound, smell, taste, and feel exactly as it did when you had a body, but you no longer have a body. You are a brain in a vat.
In this case, the argument runs, how can you be sure that you are not a brain in a vat now? If, ex hypothesi, all of your experiences would be exactly the same as they were in your former embodied state, what confidence can you have that, say, you are drinking your morning coffee rather than having that experience precisely simulated by the computer?
Through history, many people, irritated by skepticism, sought to make short work of it. Skepticism was said to be obviously self-refuting. If you say "nothing can be known," the pat reply is "How do you know?" Skeptics appear hoist with their own petard, claiming to have knowledge that they say is impossible. Skeptics may be irritating, but they are not stupid, and they reply that they are not making any claims for themselves. They are simply engaged in the practice of showing that every knowledge claim fails on its own terms, that is, every knowledge claim presupposes certain standards of rational justification, but skeptics claim to show that every such claim fails to meet its own standards or that such standards are themselves unsubstantiated. For instance, commonsense claims about everyday objects presuppose that sense perception is reliable, i.e., that our senses convey accurate information to us. However, they claim, it is easily shown how fallible every sense is, that is, how easily we are fooled into thinking we have seen, heard, touched, tasted, or smelled what we have not.
Other critics have said that skeptics cannot be sincere, otherwise they would eat poison, jump out of airplanes without a parachute, and stroll blindfolded down the middle of busy freeways. In Hume's Dialogues Concerning Natural Religion, one character dismisses another's claim to be a skeptic by saying that when the meeting adjourns, we will see if the supposed skeptic leaves by the door or the window. Jumping forward from Hume to Darwin, we would seem to expect that honest skeptics would be eliminated by natural selection. Skeptics, however, reply that, though they see no reason to accept the claims of common sense, neither do they have any evidence to the contrary. For them, all evidence is equally bad. They would not, for instance, categorically assert that strolling down the freeway is harmless. They admit that some things seem so, so they will just go with how things seem while remaining in doubt about how they actually are. Skepticism has even been used to support religion. If reason cannot prove either theism or atheism, you might as well go with faith.
My take on skepticism as universal doubt is that sometimes doubt is harder to justify than belief. I think that this was the point behind G.E. Moore's famous reply to skepticism. How do we know that there is an external world? Moore held up a hand and said, "Here is a hand." He held up his other hand and said, "Here is another hand." Hands are objects in the external world, so an external world exists. If the skeptic wants to question Moore's claim, "Here is a hand," he has to offer arguments that would justify doubt about the presence of hands in this case, but what kind of argument could do that?
True, the senses do sometimes deceive us, but in the present circumstance the lighting is good, the hands are just a few feet away, and nothing obscures the view. But couldn't we be dreaming or hallucinating hands? Couldn't we be brains in vats? But merely introducing a scenario is no reason to take such a scenario seriously. Scenarios are cheap; you can think of six before breakfast. By a wild stretch of the imagination, I guess I can visualize the brain-in-vat scenario, but if the skeptic wants me to take it seriously, i.e., as anything other than amusing science fiction, he needs to show that I might really be a brain in a vat. Put another way, sometimes the burden of proof is on the skeptic.
As philosopher John Searle notes, the human mind comes with certain default settings. We have an in-built awareness of ourselves as located in a spatio-temporal reality. For instance, humans spontaneously regard themselves as located in a space and time with objects of many different sorts located at various distances in time and space from us. This awareness arises in early infancy. Thus, I am so many kilometers from the Eiffel Tower, and Napoleon lived so many years before me. Likewise, I have the spontaneous, irresistible belief that other people have minds (thoughts, feelings, desires, etc.) like mine.
Even David Hume, the Great Skeptic himself, admitted that there were what he called "natural beliefs" that arise spontaneously and irresistibly and are impervious to skeptical quibbles, which are therefore pointless. If skeptics insist that we are not "aware" of an external world, but there only "seems" to be one, I would ask why, if something manifestly, and, indeed, irresistibly seems to be so, and there is no good reason to think that it is not so, what could possibly be wrong about regarding it as so? Of course, we could be wrong, but knowledge need not be equated with certainty, so knowing that x is compatible with possibly not-x.
If skeptics will not accept the basic deliverances of sense and reason, what, in principle, could satisfy them? If nothing could, then why play the skeptic's rigged game?
Finally, what about that damned brain in a vat? Even to understand the sentence "I might be a brain in a vat" requires that the thinker understand the meaning of those words. So, the skeptic must know something even to entertain skepticism. Further, the concepts involved in that supposition are quite sophisticated, and can only be understood in the context of a much wider web of concepts, their implications and relations. "I" requires a sense of self, that is, an awareness of a singularity that unites all the discrete elements of experience into a single, unified consciousness. Further, "self" can only be understood in contrast to not-self, things external to self. "Might" is a modal concept implying possibility, a concept that cannot be understood without the attendant concepts of actuality and necessity, and these in turn are understandable only in a context of much broader experience and thoughts.
Even "vat" requires the concept of an extended, three-dimensional object designed, in accordance with certain assumptions about physical reality, for holding a mass of liquid. "Liquid" can only be understood in contrast to the other states of matter, gas and solid. It is hard to see how, in principle, any of these concepts could be understood except in the context of causal interactions with an external world that bears objective properties corresponding to those concepts and all related concepts. After all, to understand a concept is not just to possess a subjective idea, but to know how to apply terms expressing that concept and to understand the implications of applying such terms. To really understand "vat" is to understand a world.
The point is that even to entertain a scenario like being a brain in a vat, you must understand many other concepts, and those in turn will require further concepts, some of which seem learnable only through interaction with a physical world. A toddler could not be a skeptic. Skepticism is possible only for those who already know a lot.
Skepticism as a program of universal doubt therefore seems to be unmotivated. However, skepticism in a more limited role definitely has its uses. One of the basic jobs of philosophy is to push the limits of reason, to see what the resources of reason really are once our comfortable assumptions and everyday thinking are skeptically challenged. In philosophy, nothing is sacrosanct. Even the basic "laws of logic" may be challenged. For instance, antirealist philosophers connect truth with verification; if there are no possible means of confirming or disconfirming a claim, it is neither true nor false but indeterminate. It is not that we just do not know the truth; there is no truth of the matter.
Now, we are familiar with this sort of situation in the weird, wonderful world of quantum mechanics. According to the Copenhagen Interpretation of QM, prior to measurement a quantum property such as the momentum of an electron is in no definite state, but rather a superposition of all possible states. When measured, the momentum of the electron obligingly takes on a definite value.
The antirealist philosophers extend such uncertainty to everything. Did it rain or not on my location exactly 10,000 years ago today? According to the antirealists, if we have no way of finding out, then it is neither true nor false that it rained in my location exactly 10,000 years ago. They mean it. Again, it is not just that we don't know. There is no truth of the matter. It neither did nor did not rain here 10,000 years ago. So, antirealists reject the "law of the excluded middle," that is, that for any proposition p, either p or not p. Yet the excluded middle is a tautology, a truth of logic that can be denied only on pain of contradiction. Skepticism about the law of the excluded middle leads to that great rarity, a philosophical joke: There are three types of philosophers, those who accept the law of the excluded middle and those who do not.
As a hardcore realist, the antirealist position seems to me maximally implausible. Surely, they were having some kind of weather 10,000 years ago. We most definitely can confirm that there was a world with an atmosphere 10,000 years ago, so, to lapse into the vernacular, WTF? Such antirealism appears to have other absurd consequences. Prior to the invention of the telescope, humans had no means of confirming or disconfirming that Jupiter has moons. According to antirealism, then, the proposition "Jupiter has moons" was neither true nor untrue. Then, in 1609, Galileo looked through his telescope and observed the moons of Jupiter. Are we to think that Ganymede, Callisto, Io, and Europa popped into existence when observed by Galileo? Call me skeptical.
So, skepticism has its uses in philosophical argument, but what about in our everyday activities? Absolutely it does. Your beliefs are worth a lot. Politicians, corporations, and ideologues spend vast amounts of time, effort, and money to influence your beliefs. Drug commercials are my favorites. Deliriously happy people are shown engaged in delightful activities, all thanks to the wonder drug Gulliblex. As they cavort, the announcer smoothly intones possible side effects, "may lead to blindness, seizure, or death." To sway your opinion, the belief influencers use every means, fair and foul. Mostly foul. The only way to protect your rationality (or even your sanity), is to gird yourself in the full armor of skepticism.
The skepticism I am talking about here is not the pointless universal skepticism considered above or even the philosopher's pushing-the-limits skepticism. It is the kind of skepticism found in the practice of the sciences. A new scientific claim may show much promise, but before a scientific community will accept it, it must be subjected to rigorous evaluation that makes every effort to probe its weaknesses and lacunae. If, despite assiduous efforts to refute it, the claim survives the harsh vetting process, it will be tentatively and defeasibly accepted by the scientific community. For instance, the theory of continental drift had been around for several decades before its final acceptance in the 1960's. The theory had been rejected, even derided, before irrefutable evidence accumulated in that decade. Now, continental drift, and its basis in plate tectonics, is in every geology textbook.
Yet no theory may ever be elevated to dogma. Even the most solidly grounded theories must be held in pawn to future evidence. T.H. Huxley said that the greatest of tragedies is a grand and beautiful theory destroyed by an ugly little fact. Science leaves pronouncements about "ultimate reality" to metaphysics and theology. All that science can ever do is to show that a theory or hypothesis is the most probable given everything that we presently know. Some theories are so abundantly confirmed by so many pieces of independent evidence and multifarious instances of predictive success that, for all practical purposes, they are taken as reliable and are employed as tools of inquiry. You simply could not do astrophysics without using general relativity. A famous geneticist said that "nothing in biology makes sense except in the light of evolution." Yet, even with relativity and evolutionary theory, we could specify what would prove them wrong.
So, skepticism, in the sense of demanding abundant confirmation before tentative acceptance, is fundamental for science. What about daily life? It would be impossible to maintain the standards of scientific rigor in our day-to-day judgments about what is or is not probable. Yet, living as we do in a jungle full of predators, each trying to claim your beliefs about everything from which deodorant to smear in your armpits to which religion to commit your soul, gullibility is not an option. Even if scientific rigor in its full force cannot be maintained in our quotidian lives, the scientific attitude can. This is what is normally referred to as "critical thinking."
So, if you do not want to be taken in by politicians, pundits, preachers, or anyone, cultivate skepticism as an intellectual virtue. Make it automatic to ask what the credentials of a claim are. Learn about common fallacies such as begging the question, appeal to authority, and appeal to ignorance, and learn to spot them. You will encounter them often. Learn some science. Be mathematically literate. Mathematician John Allen Paulos says that he once saw a TV weather reporter say, "There is a 50% chance of rain on Saturday and a 50% chance of rain on Sunday, so there is a 100% chance of rain this weekend." Holy mackerel. We live in a culture that takes mathematical illiteracy for granted, and the manipulators know it. Your mind is yours; fiercely guard it.
Here are some tips that I would offer for not being a sucker:
1) Do not accept any statistic from any politician or pundit until you have a chance to check it out for yourself. Read the classic by Darrell Huff, How to Lie with Statistics (1954), now seventy years old but now even more relevant. In general, the more statistically literate you are, the less likely you are to be fooled. While no source is infallible, some sources are more reliable than others. When a statistic is cited, see if the source is given. Misinformation and disinformation abound. There are whole "think tanks" and "institutes" funded by big business and the mega-wealthy that are dedicated to the misuse and abuse of statistics. Bureaucrats and university administrators are obsessed with "metrics," which have the appearance of objectivity, but all too often are garbage in/garbage out. If you stick a number on bullshit, it does not sound like bullshit anymore, but it is now sneaky bullshit. So, beware.
2) Be especially careful about claims you want to be true. Confirmation bias has been called "the mother of all cognitive illusions." Each of us probably falls for it once or more a day. The brain automatically highlights evidence that confirms our beliefs and ignores disconfirming evidence. As Michael Shermer puts it, the brain is a "belief engine." The way to combat confirmation bias is to honestly confront the arguments or evidence for the other side. I am a liberal, and intelligent conservative opinion is hard to find these days, but there are still exemplars such as Charles Sykes and his website, The Bulwark, David Brooks, Bret Stephens, Ross Douthat, and (going strong in his eighties) George Will. If you look for intelligent expressions of contrary views, you can find them.
3) Sometimes you should trust your gut. If you pull up to an ATM after dark and some questionable looking characters seem to be hanging around, trust your gut and drive away. On the other hand, when confronted with complex issues, your gut becomes your inner idiot, as author Charles P. Pierce put it in his hilarious and horrifying Idiot America
For instance, how much and what kind of gun control would be effective in preventing mass shootings is not something that can be settled by consulting your gut. You have to research it.
4) Finally, and perhaps most importantly, do not think that you cannot be fooled. You can, and if you tell yourself that you cannot, you are, in effect, volunteering to be a sucker. You have to learn the tricks of the belief influencers, and that is where a good course in critical thinking comes in. Scientists know that they can be fooled just like anyone else, and that is why they employ methods, like double blind studies, that are designed to counter the effects of confirmation bias, wishful thinking, and other distorting influences. As I say, we cannot evaluate everything with scientific rigor, but by cultivating skepticism as a virtue, we can minimize our chances of being a sucker.
Note: Anyone may copy and publish what I or my guests write, provided proper credit is given, that it’s not done for commercial purposes, that I am notified of the copying (you can just leave a comment saying where the copy is being published), and provided that what we write is not quoted out of context or distorted.
Thanks again for reading Letters … . Subscribe for free (always) to receive new posts and support my work.
Very good essay thank you. The following part was awesome “Deliriously happy people are shown engaged in delightful activities, all thanks to the wonder drug Gulliblex. As they cavort, the announcer smoothly intones possible side effects, "may lead to blindness, seizure, or death."
I
As usual, Keith Parsons provides an informative and fascinating look at his topic. But I want to put in a defense of philosophical skepticism by pointing out that it is not incompatible with believing in an observer-independent external (i.e. "physical") world. One can be skeptical of our ability to know the physical world "as it is" without having to doubt that "it is." Philosophical skepticism is a position about knowledge rather than a position about existence of the physical world.
Nor did classical skepticism necessarily embrace "universal doubt" about knowledge. Carneades, for example, evidently argued that although nothing can be known with certainty, some knowledge is more likely to be true than other knowledge, and that we should focus on what can be known with the highest degree of probability.
As it turns out, it's hard to be certain of the beliefs of the classical skeptics who led the Platonic Academy in Athens—Arcesilaus, Carneades, and Clitomachus—because no writings of theirs survive, and their arguments must be constructed primarily from rebuttals of critics. Clitomachus wrote over 400 books explaining Carneades' philosophy, and not one survives. The main thing we understand about them is that they denied that there could be any objective "criteria of truth" and they cast doubt on the idea that our senses portray the world "as it really is."
Thus the story of GE Moore holding up his hands as if that refuted skepticism demonstrates Moore's confusion about philosophical skepticism. Carneades would say that Moore's hands, which we see and perceive through our senses, are an appearance and thus not the same as Moore's real hands. He would not deny that Moore has real hands, but would deny that his real hands necessarily comport with what our senses perceive. (If Moore had read Bertrand Russell's book, The Problems of Philosophy, I think he would have comprehended the point.)
Modern neuroscience agrees with the ancient skeptics. As Jeff Hawkins, author of A Thousand Brains (2022), explains "There are no sensors in the brain itself, so the neurons that make up your brain are sitting in the dark, isolated from the world outside. The only way your brain knows anything about reality is through the sensory nerve fibers that enter the skull. The nerve fibers coming from the eyes, ears and skin look the same, and the spikes that travel along them are identical. There is no light or sound entering the skull, only electrical spikes." (p 173) He continues, "And since we do not perceive spikes, everything we do perceive must be fabricated in the brain. Even the most basic feelings of light, sound and touch are creations of the brain; they only exist in its model of the world." (p 174)
This means that we don't perceive the world; what we perceive is instead a sensual "stand-in" for the world, a "virtual reality" created by the brain. Hawkins again, "The truth is, we perceive our model of the world, not the world itself or the rapidly changing spikes entering the skull. As we go about our day, the sensory inputs to the brain invoke the appropriate parts of our world model, but what we perceive and what we believe is happening is the model. Our reality is similar to the brain-in-a-vat hypothesis; we live in a simulated world, but it is not in a computer—it is in our head." (p 175)
Thus, we do not "perceive" the world; what we "perceive" is a virtual reality or simulacrum created by the brain which evolved to stand-in for the world, and which provides the organism (hopefully) with a reliable basis for action. In this context, philosophical skepticism begins to make a lot of sense.
Biological organisms like us have no way of perceiving or knowing the organism-independent external ("physical") reality. What we "know" is the "virtual reality" and corresponding cortical "model" which the brain creates and presents to us from hints the body has obtained via its sense organs. This virtual reality is what we naively mistake for the external world around us.
Pragmatic empiricism—the method of the sciences—coordinates the relationship between the model of the world created thusly by our brains and the actual "physical" external world which which our bodies interact (the world our brains can never actually "know"—what we can "know" is the virtual stand-in).
Anyway, philosophical skepticism has legs in the 21st century.