Today is a rather odd coincidence day, the birthday, one year apart, of two Scottish philosophers, Thomas Reid (1710) and David Hume (1711). In his day, Reid was perhaps the more influential, but nowadays Hume has the upper hand, although both have been superseded. I’ll give you a small taste of their ideas, and of their critiques of one another, but my major point is to examine why we should care about the philosophy of knowledge and reason at all. Reid and Hume were pillars of what is now called the Scottish Enlightenment, the era that saw the flourishing of rigorous scientific method and the championing of reason over faith. The current pseudo-debate over science versus religion is an outgrowth of ideas generated in the 18th century, and the debates within the philosophical community of the era are germane to concerns we have nowadays – most especially political and social concerns. The question I ask continually in my own research is: “Why do people cling to ideas – often fervently – when they fly in the face of demonstrable facts?” Reid and Hume both had their answers to that question, radically different answers, involving the consideration of the question: “What is a fact, and how do we know it is true?”
Reid was the founder of the Scottish School of Common Sense, that is, “common sense” with a special philosophical meaning (sensus communis – natural senses humans have in common), not the popular meaning. According to Reid, our common sense is built on innate ideas (ideas we are born with). Hume denied the existence of innate ideas, believing that our ideas develop purely from our learned experience. Reid believed, for example, that we are born with a sense of right and wrong – very Scottish Protestant of him, I am sure. His moral philosophy is reminiscent of Roman stoicism in its emphasis on the agency of the subject and self-control. He often quotes Cicero, from whom he adopted the term “sensus communis”. Reid’s answer to Hume’s sceptical and naturalist arguments was to enumerate a set of principles of common sense (sensus communis) which constitute the foundations of rational thought. Anyone who undertakes a philosophical argument, for example, must implicitly presuppose certain beliefs like, “I am talking to a real person,” and “There is an external world whose laws do not change,” among many other positive, substantive claims. For Reid, the belief in the truth of these principles is not rational; rather, reason itself demands these principles as prerequisites, as does the innate “constitution” of the human mind. It is for this reason (and possibly a mocking attitude toward Hume and Berkeley) that Reid sees belief in the principles of common sense as a litmus test for sanity. For example, in The Intellectual Powers of Man he states, “For, before men can reason together, they must agree in first principles; and it is impossible to reason with a man who has no principles in common with you.”
Hume’s empiricist approach to philosophy places him with John Locke, George Berkeley, Francis Bacon and Thomas Hobbes as a British Empiricist. Beginning with A Treatise of Human Nature (1738), Hume strove to create a total naturalistic science of humans that examined the psychological basis of human nature. Against philosophical rationalists, Hume held that passion rather than reason governs human behavior. Hume argued against the existence of innate ideas, positing that all human knowledge is founded solely in experience.
In what is sometimes referred to as Hume’s problem of induction, he argued that inductive reasoning and belief in causality cannot be justified rationally; instead, our trust in causality and induction result from custom and mental habit, and are attributable only to the experience of “constant conjunction” of events. This is because we can never actually perceive that one event causes another, but only that the two are always conjoined. Accordingly, to draw any causal inferences from past experience it is necessary to presuppose that the future will resemble the past, a presupposition which cannot itself be grounded in prior experience.
Hume was also a “sentimentalist” who held that ethics are based on emotion (or sentiment) rather than abstract moral principles, famously proclaiming that “Reason is, and ought only to be, the slave of the passions.” Hume maintained an early commitment to naturalistic explanations of moral phenomena, and is usually taken to have first clearly expounded the is–ought problem, or the idea that a statement of fact alone can never give rise to a normative conclusion of what ought to be done. Hume influenced utilitarianism, logical positivism, Immanuel Kant, the philosophy of science, early analytic philosophy, cognitive science, theology, and other movements. Kant himself credited Hume as the spur to his philosophical thought who had awakened him from his “dogmatic slumbers”.
So, why should you care about any of these debates? Right now they are important because they are crucial to understanding the state of the world today. What is the status of knowledge and rationality these days? At election time do people look at the candidates on offer, assess all the information available to them, and then vote rationally? I think you know the answer to that question. People favor candidates for many reasons, and logic is rarely in the mix when they make their choices. As often as not they choose candidates who are going to work against their own interests and/or the interests of the country – and the evidence that they will do this is in plain sight. But they vote for them anyway. Why? Much of it has to do with embedded ideas based on sentiment that cannot be changed by facts. Then we have to ask: How do we stop people from behaving irrationally, especially when their decisions negatively impact others in dramatic ways? Good question. Such questions cannot be explored sensibly without knowing how people think, and our understanding in this regard is still pitiful.
On that note let’s turn to cooking. What knowledge do you need to possess to follow a recipe successfully? Recipes from 200 years ago made gigantic assumptions about what the cook who read them already knew. They were of the style: “Take some of this and a bit of that and boil it over a brisk fire until it is done.” Contemporary recipes are much more specific when it comes to ingredients, preparation, quantities, timing, temperatures, etc., but an enormous amount is still left unsaid, or assumed. I can give identical recipes to two different cooks, and even when following the recipes to the letter they will produce notably different dishes. Years ago I used to make Argentine tortillas for my girlfriend all the time, and she asked me to teach her how to make them. First, I showed her – step by step – then I stood over her and supervised her as she cooked one. We did this multiple times, and yet she never could replicate my method, and her tortillas were nothing like mine. Somehow our knowledge base was not the same. The knowledge base of expert cooks is a mystery. I travel so much because it’s the only way to taste the dishes of the world. People who have devoted their lives to hand making rice noodles, roasting duck, or slow baking tripe in their corners of the world, make dishes that cannot be replicated by anyone else. You have to go to where the cooks live and work to sample their wares.
For today’s recipe think of those dishes that you know from the hands of one cook only. They could be a memory of a favorite grandmother, or a special delight you experienced on a trip. I think of my father’s ravioli or my mother-in-law’s fried chicken; I think of my favorite Kunming duck and a little baklava shop in Istanbul.