Chess players seeking to assess a position need to anticipate the best moves that can be made by their opponents. Similarly, in considering any philosophical problem, we should take seriously the strongest arguments that can be offered by those who disagree with us. As John Stuart Mill wrote in On Liberty, “He who knows only his own side of the case, knows little of that.”
Mill’s principle implies that if you are unable to make a case against your own stance, then you don’t understand the matter as well as you may suppose. For that reason, one of my favorite strategies in oral exams is to ask candidates their position on an issue, then invite them to explain the most challenging arguments against their own. For instance, I ask defenders of materialism how to make the case for dualism, defenders of democracy how to make the case for aristocracy, or defenders of a right to choose how to make the case for a right to life. At first, those who are asked such a question presume that I have misunderstood which position they are defending, but I assure them that I am aware of their view but am seeking the best arguments against theirs. Some fall silent, saying that they don’t know any worthwhile arguments against their own. I remind them that philosophers of the first rank have defended an opposing position, and I am only asking on what basis they do.
Students then make their best attempts to argue against their own views. In response, I ask how they would answer the arguments they have just presented, and quickly they regain their footing and respond with assurance. Then I ask how opponents would reply to them, and this time only those who have a thorough understanding of the matter can answer effectively.
Teachers in class can also fall victim to a failure to do justice to intellectual opponents. Whenever an instructor states opinions not shared by other reputable scholars, students ought to be so informed. They are entitled to know whether their teacher is expressing a consensus or only a majority or minority viewpoint. For an instructor to defend personal beliefs is appropriate, but serious alternatives should not be neglected. Teachers should ask themselves: If another qualified instructor were in my place, might that individual offer judgments that conflict with those I have presented? If the answer is affirmative, teachers should alert students, thereby increasing their understanding of the relevant issues.
For instance, I believe that free will and determinism are incompatible, and when I teach this issue, I argue for my position. I also emphasize, however, that my view is likely a minority opinion, hence I do my best to explain as persuasively as possible the arguments that have been offered by those who disagree with me.
Consider another example. I know of no better way to teach Anselm’s ontological argument for the existence of God than to present the argument step by step, then ask students what if anything is wrong with the reasoning. As they offer their criticisms, I defend the argument against them. Then I offer this challenge: Given that the mere definition of a concept such as square circle is sufficient to disprove its existence, why cannot the mere definition of God be sufficient to prove God’s existence? Any knowledgeable opponent of the ontological argument should have carefully considered this question. Those not aware of it have given insufficient attention to how the argument might be defended. Eventually, I explain why many philosophers, myself included, do not accept the argument, but the key point is that students can appreciate the strength of the argument only if I defend it seriously.
Philosophers devote much effort to developing arguments that support their positions, but they should carefully consider the arguments against their own. To cite Mill once again: “Ninety-nine in a hundred… called educated… have never thrown themselves into the mental position of those who think differently from them and considered what such persons may have to say; and, consequently, they do not, in any proper sense of the word, know the doctrine which they themselves profess.” Here is a wise lesson for faculty and students alike.
Steven M. Cahn
Steven M Cahn is Professor Emeritus of Philosophy at the City University of New York Graduate Center. Among the recent books he has authored are Teaching Philosophy: A Guide (Routledge, 2018); Inside Academia: Professors, Politics, and Policies (Rutgers, 2019); Navigating Academic Life: How the System Works (Routledge, 2021); Professors as Teachers (Wipf and Stock, 2022), and, most recently, From Student to Scholar: A Candid Guide to Becoming a Professor, Second Edition (Wipf and Stock, 2024).
A very solid and substantive viewpoint about the nature of philosophy in relation to teaching of philosophy. I have taught more than fifty different courses in both Western and Eastern philosophy over more than five decades and have practiced Prof. Cahn’s ideas in my own way. My way is to play the Devil’s advocate, no matter what position I personally hold. I argue strongly against every student’s stated position to bring to them the strength of the other side from their assumed truth. Yes, it costs some unhappy and irritated students. But the nature of Parmenedian dialectic as dialog of opposing philosophical positions is brought out in good relief. Thank you, Prof. Cahn, for articulating a needed substantive point about the importance of philosophical dialectic.