T H E P H IL O S O P H IC A L P U R S U IT OF KNOWLEDGE Baron Reed Northwestern University Famously, Aristotle begins his Metaphysics with the claim that “All men by nature desire to know.” But what is knowledge, and what can we know? These questions have been answered in very different ways in the history of philosophy. Seeing how epistemology—the study of knowledge—has been shaped by the great philosophers of the past can help us understand the role knowledge plays in modern culture. One of the central threads in the philosophical tradition takes knowledge to amount to certainty. The Stoics, for example, thought that a sage would never believe anything false and never hold mere opinions. Knowledge of this sort was supposed to arise from the “craftsmanlike” impressions the world makes upon the mind. When these impressions are combined in the right sort of way, they form a body of scientific knowledge that becomes impervious to doubt. For the Stoics, then, perfection may be difficult—indeed, it’s unclear whether they thought anyone had ever managed to become a sage—but it is within our reach, at least in principle. In the Early Modern period, Descartes advanced a view similar in many ways to that of the Stoics, though he thought that our “clear and distinct perceptions”— those that afford us certainty—were largely given to us by God. In the creation of the human mind, God instilled the very ideas that also serve as the natures of the things to be found in the created world. That’s why, for Descartes, mind and world fit together like a lock and key. Although our minds, as they currently exist, have been distorted by the errors of past generations and by an over-reliance on the senses, it is nevertheless possible for us to perfect our minds. We may never know as much as God does, but what we do come to know will have the same certainty as God’s knowledge. This optimistic thread in the philosophical tradition has been opposed from the beginning by the skeptics. The Academics of the third century BCE, who took up the sort of questioning attitude Socrates had embodied, were the great rivals 2 of the Stoics. They denied that any of our impressions could be so craftsmanlike that false ones just like them couldn’t be found. How could you know, for example, that the man in front of you is the same neighbor who has lived next to you for years when, for all you know, he might have an identical twin? And, even if he doesn’t actually have a twin, you might be dreaming or hallucinating his presence. If so, it doesn’t matter how closely your impression conforms to reality—a false one could appear to conform just as well. Descartes, of course, also fretted about the possibility that you might be having an exceptionally vivid and entirely coherent dream, though this is a problem he raised against himself. Such was his optimism in the philosophical system he was creating, Descartes thought he could use skeptical arguments to trip up Aristotelians who could not trace their views back to an indubitable foundation. The possibility that you are dreaming—and the even more worrying possibility, raised several centuries earlier by al-Ghazali, that there is a sort of experience more perfect than what the senses provide and to which you will someday awaken—leads to skepticism about perception. Descartes also raised a far broader skeptical challenge, targeting not only perception but also our rational capacities: until you know how your mind came to be what it is, you cannot be certain it isn’t radically out of tune with reality. Like a poorly programmed computer, it might simply be making the same errors over and over, as every attempt to find the truth path instead takes it further into the wilderness. To encapsulate this thought, Descartes encourages his reader to imagine that she is being deceived in every possible way by an evil demon. Many philosophers have worried that there is no hope of return from a skepticism so all-encompassing. Any move you make in response would necessarily involve the use of your own mind’s capacities—and these are precisely what is in doubt. Even if this worry can be set aside, Descartes still failed to convince anyone that his response to skepticism would take us very far. That response begins with the celebrated cogito—I think, therefore I am—but then quickly becomes mired in a number of highly contentious metaphysical premises. The Cartesian system threatens to collapse into a solipsism of the present moment: I exist at this moment, but beyond that all is in doubt. In these two central episodes in the history of philosophy—the Stoics’ clash 3 with the Academics, and Descartes’s conflict with his own skeptical arguments— we can see both the clearest defense of an epistemology that aims at certainty and the most compelling reasons to abandon it. Most philosophers now have aims that are relatively modest by comparison. But if knowledge is something less than perfect certainty, how exactly should we understand it? In the mid-twentieth century, there seemed to be a consensus around the view that someone has knowledge when she has a belief that is both true and justified. For example, knowing that it rained earlier today because you see wet sidewalks and drops falling from the branches of the trees is very different than simply guessing it rained on no basis at all, even when your guess happens to be right. It is an advantage of this sort of view that it permits us to have knowledge without requiring perfect certainty. It’s possible, of course, that someone sprayed water all over the neighborhood outside your window in an effort to deceive you, but that sort of thing is quite rare. So, you can rely on your evidence as a good, though less than perfect, guide to how things are. This modest consensus has been successfully undermined, in one of the more curious twists in recent philosophical history. An otherwise obscure philosopher named Edmund Gettier published a paper less than three pages in length, in which he pointed out that knowledge cannot be a mere combination of truth and justification, for those two things could arise independently of one another. Suppose that you see a shaggy, white animal in the distance and come to believe that there’s a sheep in the meadow. A sheep really is there, but it’s behind the animal you’re actually looking at: a sheepdog whose fur has been trimmed to make it look like a sheep. Your belief that there’s a sheep in the meadow is both true (because of the sheep) and justified (because of your sensory evidence from the looking at the sheepdog), but this seems to be a lucky coincidence—not the sort of thing that could count as genuine knowledge. The Gettier problem, as this has come to be known, has spawned a vast literature, in which dozens of proposed solutions have fallen victim to increasingly elaborate counter-examples. No solution has won general acclaim in more than five decades of attempts, and the ongoing failure has left some philosophers pessimistic about our chances of ever being able to fully say what knowledge is. As the consensus about what knowledge is has been undone, a variety of 4 new debates have arisen in epistemology. One of them divides philosophers on their most basic understanding of how to think about human cognition. On one side are philosophers who argue that knowledge is a natural phenomenon, no different than the way bees construct their hives and chimpanzees form social hierarchies. Knowledge, understood in this way, is just the right sort of reliable fit between an animal’s mind and its environment. Human knowledge may often be more sophisticated and systematic than that of the other animals, but it is essentially the same sort of thing. On the other side of this debate are philosophers who think that human knowledge is different not only in degree but in kind from what can be found in non-human animals. Although we do share our basic perceptual faculties with other animals, humans differ in having a rational, reflective capacity overlaying them. Even the evidence from the senses has to be able to pass a rational review, as it might need to be weighed against countervailing evidence. Humans are also capable of vastly more sophisticated modes of inquiry, including especially the sharing of complex bodies of information with one another. What all of this means, on this way of thinking, is that rationality is central to our best understanding of knowledge. Rationality was vitally important to Descartes, too, but his focus was almost entirely confined to the egocentric perspective: what do I know? Recent philosophers have increasingly turned their attention toward a broader question: what do we know? It is very common to speak as though collective bodies— corporations, universities, governments, and so forth—know things (and intend to act on that knowledge). But what does it mean for a collective body to have knowledge (or intend to act on it)? It cannot simply be a matter of every member of that body having the knowledge in question; groups often include dissenting members, and there will usually be non-essential members who are left uninformed about policy decisions and the reasons for them. The question becomes all the more important when questions of responsibility arise. Is it, for example, just the corporation itself that’s responsible for violating laws regulating pollution, or should the head of the division responsible for the wrongdoing also face criminal charges? As is usually the case, responsibility belongs especially to those who know, or should know, the relevant facts. The link between epistemology and ethics has also been developed in other 5 ways. Some philosophers have argued that a focus on either the reliability of our cognitive abilities or on evidence is too narrow. Both leave out any attention to what Aristotle called the intellectual virtues—traits like open-mindedness, intellectual humility, and carefulness—and consequently lose the connection between knowledge and an intellectual life that is well-lived. This broader perspective—if a compelling one can be found—holds the promise of explaining not only what value we find in knowledge but also in tracing its connections to understanding and wisdom. It is a further question how epistemic values—knowledge, evidence, and the like—interact with values of other sorts. The American philosopher, William James, noted that there can be cases in which it seems that you ought to have a belief even when it conflicts with what your evidence tells you. He says, for example, that a hiker in the mountains may find herself stuck in a spot where she cannot climb out by going either up or down; her only choice is to attempt to jump across a chasm that is wider than she has ever managed to leap. The odds are not in her favor, but if she can get herself to believe that she is capable of making the jump, her confidence will at least make success a bit more likely. When faced with the choice between improving her odds of surviving the jump and having the true belief that she probably won’t make the jump, James thinks it’s clear what the hiker should do: she should believe she’ll make it, even against what her evidence tells her. But if it is acceptable to believe against your evidence in this case, when doing so might help save your life, why not do so whenever it would serve your interests? If it will help you succeed in an upcoming job interview to believe you are handsome and charismatic—even though all the evidence you have from both your friends and your mirror indicates otherwise—what’s stopping you? Some philosophers want to say that it is a simple fact that knowledge is intrinsically valuable, but this doesn’t answer the question in a very deep way. After all, if we want to know why we should care about knowing what the facts are, it does no good to respond by just pointing to another fact. Perhaps a better way of explaining the value of knowledge is to show how it is inextricably bound up with other things we value. It’s clear that humans are deeply social animals. This means, not only that we are very useful to one another 6 as sources of information about the world around us, but also that it is uncomfortable for us to be in a position of disagreement with one another. It nevertheless happens quite frequently that we do find ourselves disputing matters of importance, and we need some way of coming to a shared point of view. There is a constant temptation for the powerful to use violence and deception to bring others to accept their preferred set of beliefs—but this is a terrible mistake. Think, for example, of the Dreyfus Affair a century ago in France. On the basis of very weak evidence, an army captain was convicted of treason and imprisoned for years. His family, along with various intellectuals, protested against the injustice involved in the legal proceedings. Government and military elites continued to insist Dreyfus was guilty, long past the point when it was obvious the true criminal was someone else—indeed, someone whose false testimony had played a major role in Dreyfus’s conviction. Without a shared commitment to how disagreements could be resolved—i.e., by honoring the evidence, wherever it may lead—the conflict stretched out for years, fracturing society in ways that were still visible decades later in World War II. The lack of epistemic integrity of the conservative government became a form of moral bankruptcy, and this ultimately proved its own undoing. Philosophers may never reach a new consensus on the nature of knowledge— whether it is certainty or something less—and they will very likely face skeptical challenges for as long as philosophy survives. But these sorts of disagreement are themselves only possible because philosophers agree in the most important ways: it is the pursuit of knowledge, through the civil exchange of evidence and reasons for belief, that represents the very best humans are capable of.