University of Connecticut OpenCommons@UConn Doctoral Dissertations University of Connecticut Graduate School 5-4-2017 Hume's "Of scepticism with regard to reason" Benjamin M. Nelson [email protected] Follow this and additional works at: https://opencommons.uconn.edu/dissertations Recommended Citation Nelson, Benjamin M., "Hume's "Of scepticism with regard to reason"" (2017). Doctoral Dissertations. 1458. https://opencommons.uconn.edu/dissertations/1458 Hume’s “Of scepticism with regard to reason” Benjamin Nelson, PhD University of Connecticut, 2017 Abstract: The arguments in “Of scepticism with regard to reason” get their start from Hume’s claim that, thanks to our “fallible and uncertain faculties,” we must “check” any present judgment from reason in a step of corrective reasoning (T 1.4.1.1; SBN 180). A corrective step is meant to “correct and regulate” present judgments from reason through reflection on past judgments from reason (T 1.4.1.5; SBN 181-82). Hume argues that this ushers in the extinction of knowledge and belief because reflection on past judgments will inevitably diminish our assurance for any present judgment. Why Hume thinks diminishment is inevitable has remained elusive. The key, I contend, is that our assurance for judgments diminishes because of what must be presupposed in order to make and accept them. Explicit consideration of the possibility that our present reasoning is mistaken would keep us from making or accepting any present judgment from reason. So to reach any judgment by reasoning, we must presuppose that we are reasoning legitimately, that is, from the right evidence and in the right way. Past judgments from legitimate reasoning are evidence that this presupposition is true while past judgments from erroneous reasoning are evidence that it’s false. Because legitimacy must be presupposed, the former evidence is accounted for in any present reasoning while the latter evidence is not. Accordingly, past errors afford unaccounted- for evidence that, when explicitly considered in a corrective step, can only diminish our present assurance. However, to stand pat with respect to a corrected judgment is to presuppose that it has been reached by legitimate reasoning. Past errors are evidence that this presupposition is false and that we’ve made the wrong corrected judgment. This prompts further reflection, which leads to further diminishment, which prompts further reflection, and so on until our first assurance is diminished to nothing—hence the extinction of knowledge and belief. Thus, Hume’s skeptical conclusions follow from reflecting on past judgments in successive corrective steps because the legitimacy of our present reasoning must be presupposed in order to make and accept any present judgment from reason. Hume’s “Of scepticism with regard to reason” Benjamin Nelson B.A., University of South Florida, 2008 M.A., University of Connecticut, 2013 A Dissertation Submitted in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy at the University of Connecticut 2017 i Copyright by Benjamin Nelson 2017 ii APPROVAL PAGE Doctor of Philosophy Dissertation Hume’s “Of scepticism with regard to reason” Presented by Benjamin Nelson, B.A., M.A. Major Advisor _________________________________________________________________ Donald Baxter Associate Advisor ____________________________________________________________ Michael Lynch Associate Advisor _____________________________________________________________ Lionel Shapiro University of Connecticut 2017 iii Acknowledgments It’s difficult for me to believe that I’m writing the acknowledgements for this dissertation, and that’s only partly because I’ve been wrestling with Humean skepticism for the last three years. Developing these ideas and getting them onto the page in a coherent form was a task I couldn’t have managed without the guidance and support of my committee. I want to thank Don Baxter, Michael Lynch, and Lionel Shapiro for taking the time to read my work and for helping to improve it with thoughtful comments and challenging ideas. But I would like to especially thank Don, who was unbelievably generous with his time and showed a Zen-like patience through a seemingly endless flood of pages. I can’t say whether it seemed a burden to him because he was always gracious, always ready with inciteful comments and criticisms, and always willing to talk through one more puzzle. I have learned a great deal from him and my work has been made substantially better for his efforts. Indeed, without Don’s encouragement and commitment to this project, it would never have been completed. Now that it’s done, I sincerely hope it’s something for which he shares some measure of pride. I would also like to thank JP Naan, who has been an incredible friend to me. His questions and conversation helped me to develop and clarify many of the ideas in this dissertation. I’m grateful for his friendship. My parents, Mike and Carmen, and my sister Jillian have given me extraordinary love and support. I want to thank them for being a constant source of encouragement and relief. I also want to thank my extended family, Rita, Paul, and the (notorious) Forbes sisters for their kindness and laughter. They all helped to remind me that there was a world beyond Hume. Above all, I want to thank Kristin Forbes. We have loved each other for over a decade and have been friends even longer. I have no doubt that finishing this dissertation and completing graduate school would have been impossible without her. Kristin believed in me. She helped keep me upright. She let Hume take over our dining room table. I wish I could fully express my gratitude for everything she is and for everything she means to me. I can’t imagine my life without her. iv Contents Introduction: 1 Chapter 1: Hume’s Three Senses of “Probability” and Two Types of Probable Reasoning 11 Chapter 2: Errors in Reasoning and Accidents of Nature 66 Chapter 3: Epistemic Presuppositions and Inevitable Diminishment 109 Chapter 4: The Degeneration of Knowledge in Practice 145 Chapter 5: The Diminishment of Belief and the Extinction of Evidence 176 Chapter 6: Answering Objections and Alternative Interpretations 198 References: 259 v Introduction Hume’s “Of scepticism with regard to reason” is just over four pages long. This dissertation, which runs well over two-hundred pages, focuses on just the first two. Obviously, more needs to be said. But for now, I have to rest content with addressing Hume’s central arguments in this difficult section of the Treatise. I mention its shortness because it makes Hume’s conclusions there all the more striking. In just two pages, Hume takes himself to have shown how reasoning as we should entails the extinction of knowledge and belief. More carefully, he argues that when we reason responsibly, the assurance of knowledge must degenerate to the assurance of probability, and the assurance of probability must diminish to nothing. Hume famously describes this as “a total extinction of belief and evidence” (T 1.4.1.6; SBN 183).1 The arguments are puzzling. But from an initial reading, you feel like you’ve nearly understood how they’re supposed to work. The broad outlines are clear enough in that the arguments have something to do with our fallibility. We sometimes make mistakes when reasoning. That’s a relevant piece of data for anyone who cares about the trustworthiness of their judgments. So if we’re being responsible, we ought to take this fact into consideration when making judgments on the basis of reasoning. But admitting that we sometimes make mistakes forces us to admit that any instance of reasoning might be mistaken. And from this admission, we’re bound to lose confidence in any judgment reached by reasoning. As a result, we can’t be fully certain about any conclusion from 1 References to the Treatise are to David Hume, A Treatise of Human Nature, ed. David Fate Norton and Mary J. Norton (Oxford: Clarendon Press, 2000), hereafter cited in the text as “T” followed by Book, part, section, and paragraph, and to A Treatise of Human Nature, ed. L. A. Selby-Bigge, revised by P. H. Nidditch, 2nd ed. (Oxford: Clarendon Press, 1978), hereafter cited in the text as “SBN” followed by page number. 1 demonstrative reasoning, which means “all knowledge degenerates into probability” (T 1.4.1.1; SBN 180). Likewise, our assurance for any judgment reached by probable reasoning must somewhat diminish when we consider that it may have been reached in error. But we’re not done yet. It’s possible that we’ve made some mistake in accounting for the possibility of a present error. From this admission, our assurance for a present judgment is bound to diminish even further. But again, we may have made some mistake in reaching this twice diminished judgment. Reflecting on this fact leads to further diminishment, which prompts further reflection, which leads to further diminishment, and so on until we reach a stage where we’re left with no assurance at all, that is, we reach a total extinction of belief. On a first read that is sufficiently brisk, the arguments look like they basically work. Hume encourages our optimism when he sums up the thrust of the arguments by reporting that “when I reflect on the natural fallibility of my judgment, I have less confidence in my opinions” (T 1.4.1.6; SBN 182-83). Surely that’s right. When I remember that I’m terrible at math, I double check even the simplest additions. When I recall that I make mistakes about mundane things like restaurant-hours, I’m forced to google before going to dinner. What’s more, Hume suggests that time devoted to fully understanding the arguments will not be wasted since he assures us that we will “find no error in the foregoing arguments” (T 1.4.1.8; SBN 183-84).