 Hi, I'm Peter Adamson and you're listening to the History of Philosophy podcast, brought to you with the support of the Philosophy department at King's College London and the LMU in Munich. Online at www.historyoffilosophy.net. Today's episode, No Uncertain Terms – 13th Century Logic Whatever you think of Bill Clinton's performance as US President, you cannot deny that he would have made an excellent scholastic philosopher. Admittedly, the monastic lifestyle might have presented him with some difficulties, but Clinton was able, in the midst of a cross-examination, to come up with the line, it depends upon what the meaning of the word is is. Clearly this is a man who would have been right at home in a medieval disputation. Clinton's ease with such fine distinctions was acquired through his training in law, another reason to think he would have found the medieval university a congenial setting. But the medievals who really got to the bottom of the meaning of the word is, and quite a few other words into the bargain, were those who taught and wrote about logic. With today's look at this topic, I'm kicking off a mini-series devoted to developments in several departments of philosophy during the 13th century. Episodes on natural science, the soul, metaphysics, and ethics will set the table for the feast of philosophy that comes in the works of major figures like Roger Fakin, Bonaventure, Albert the Great, Thomas Aquinas, Duns Scotus, and Henry of Ghent. Along the way, we'll whet our appetite by sampling the ideas of some lesser-known figures whose historical impact far exceeded their present-day notoriety. The 13th century was a time of great intellectual upheaval, as new ideas from Aristotle and the Islamic world reshaped all philosophical disciplines. Nowhere was the impact of these sources more immediate or far-reaching than in logic. The result was the greatest period of development in this discipline between the invention of logic by Aristotle and the work of Gottlob Frege in the 19th century. Of course, logic had been a standard part of the curriculum for centuries already, in the guise of dialectic, one of the arts covered in the Trivium. And Aristotle was already central to the study of dialectic during the 12th century. So the change was not a sudden rediscovery of Aristotelian logic as such. It was rather the expansion of the logical works now available, and the increase in the number and sophistication of logical textbooks and commentaries. To mark this distinction, the medievals themselves referred to the Aristotelian texts that had long been available in the translations of Boethius as the Old Logic, whereas the works that had become available more recently were called the New Logic. It may seem perverse to call equally ancient things old and new, but as Bill Clinton might put it, sometimes it depends upon what the meaning of the word new is. We can already see this process of recovering Aristotle in John of Salisbury, that most well-read man of the 12th century. Along with his pioneering political treatise, the Polycraticus, John composed another work with a Greek-style name, the Metalogicon. At the outset of the work, he announces that he is taking issue with a man he calls Cornificius. The gesture is a typical sign of John's antiquarian literary taste. Cornificius was a critic of Virgil whose name is being borrowed for the occasion. Whoever he really was, John's opponent didn't like the arts of the trivia. He dismissed dialectic as pointless, probably because of the poor teaching he received. John describes how classes would become so consumed with pedantic complexity that participants would bring along a bag of peas, counting them out one by one to keep track of multiple negations. Cornificius was thus led to adopt the opposed view that whatever is useful in the study of language and argument can be learned quickly and easily. Against him, John argues passionately that the arts of the trivium are anything but trivial. Without grammar, one cannot use words properly, without rhetoric, one cannot use them eloquently, and without dialectic, one cannot pursue philosophy itself. John still represents a 12th century mindset, as is clear from his interest in authors like Virgil and Cicero, his frequent allusions to Marciano Scapella and his praise of the thinkers of Schacht as the greatest teachers of the age. But he's already aware of more logical works than had been used by, say, Bernard of Schacht. He explains the usefulness of the whole of Aristotle's Organon, or collection of logical works, including the so-called New Logic. This included the Prior Analytics, which systematically surveys the types of valid syllogism, the Topics, which studies dialectic, and the Sophistical Refutations, which offers a diagnosis of misleading, invalid arguments. These are the works that are going to revolutionize logic among 13th century thinkers. They will take to heart John's declaration that no one who fails to master the analytics can call himself a logician. Before the student of logic can proceed to the syllogistic arguments of the analytics, though, he will first need to learn about the parts of arguments. These parts will be the individual premises of syllogisms, and even more basically, the terms that appear in those premises. If for instance our syllogism is, Giraffes are ruminants, all ruminants have four stomachs, therefore giraffes have four stomachs, then the first premise is giraffes are ruminants, and it includes the terms giraffe and ruminant. This way of understanding the study of logic was established in antiquity, when it governed the interpretation of Aristotle's works on logic. His categories was thought to address the topic of individual terms, and his on-interpretation deals with whole propositions. The Prior Analytics would complete the job by looking at how one should put together propositions to form valid arguments. The Sophistical Refutations, meanwhile, shows how not to do this. All of this was a perfect fit for the new universities in Paris, Oxford, and elsewhere. Since students were so often asked to participate in disputation, it was urgent that they master the skills and rules of argumentation. That included being able to spot bad argumentative moves made by your opponent, which is where the study of Sophistical Arguments came in. Actually, there's a chicken and egg problem here. Were the schoolmen so interested in logic because of their educational culture, or did that culture only develop because of the availability of Aristotle's entire logic? There is truth in both alternatives. Disputation was already a feature of 12th century education, but 13th and 14th century logic reached new heights of technical sophistication, thanks to the encounter with Aristotle. In the first half of the 13th century, progress was made especially in understanding individual terms. For this reason, the logicians of this period are credited with devising what is called terminist logic. This is not to say that their writings dealt only with terms, only that the sections they devoted to terms contained their most innovative proposals. Two particularly important early terminists were William of Sherwood and Peter of Spain. Active in the 1230s and 40s, they both wrote overviews of logic, with substantial sections devoted to the analysis of terms. Somewhat later, their work was taken up and further developed by Nicolas of Paris and the author of a text called simply Logica. This is ascribed to Lambert of Auxerre, but its authenticity isn't certain. Especially the textbook by Peter of Spain will be used by later writers like John Buridan. Some of the advances made by the early terminists were practical ones, which enabled them to do advanced logic without the use of quasi-mathematical symbols or quotation marks, neither of which were in use at this time. Like any natural language, Latin grammar frequently allows for ambiguity. The sentence, omnis camelo par dos homo non est, for instance, can mean, not every giraffe is a human, or every giraffe is not a human. To avoid such problems, our logicians simply laid down the artificial rule that not affects what comes directly after it in a sentence. Another slightly more colourful example would be a mnemonic device devised by the logicians to help them recall the main properties of syllogistic arguments. Had he been a 13th century scholastic, though Clinton would have been disappointed to discover that Barbara was not an intern coming to help out with the logic class, it was rather the first of a set of clever nicknames given to the syllogistic moods. Each letter in the name has a significance. For instance, the three A's in Barbara indicate that the first premise, second premise, and conclusion of the relevant syllogism all involve affirming something universally, like when I say all giraffes are animals. As I've said, the more substantive proposals made by the terminus have to do with the individual terms that appear in the propositions that can serve as premises and conclusions in a syllogism. Aristotle's logic dealt with what is called categorical logic, from the Greek katagoren, which means to predicate one thing of another. In other words, he was interested in propositions like, Socrates is human, where the predicate human is ascribed to the subject Socrates. Of course, we can also say that a predicate fails to apply to a subject, as when we say Hiawatha is not human. So there's another reason Bill Clinton would have made a good medieval logician. He was expert at issuing categorical denials. Back in the 12th century, Abelard had already pointed out that there was a big difference between merely formulating such a predication and actually asserting it. His theory of dicta, things that can be said, played a role in his nominalist position on universals, but it was more basically a point of logic. A dictum, such as Hiawatha's being a giraffe, does not yet assert that Hiawatha actually is a giraffe. To do that, you must deploy the verb is, or in Latin est, Hiawatha is a giraffe, or if you prefer, Hiawatha camelo pados est. Logicians then, as now, called this verb a copula. One thing we can see from this example is that not all the terms in such a proposition are categorical, that is, standing for a subject or predicate. Rather, we must add another kind of term, a copula, in order to have an assertion at all. And there are many other terms that play a non-categorical role in propositions. If I say every giraffe is an animal, or Bill Clinton is sometimes faithful, the words every and sometimes seem to be modifying either the terms of the proposition or the way that the predicates are attached to the subject. We might say that such terms come along with the subject and predicate. Indeed, this is what the medievalists did say. Alongside catagorimatic terms that refer to the subject and predicate of the preposition, they recognized syn-catagorimatic terms, adding the prefix syn- which means with in Greek. This vocabulary was actually borrowed from grammar, showing yet again the interplay of the three arts of the triveum. Much of the technical discussion in terminus logic involved syn-catagorimatic terms. Take for instance these so-called modal terms necessarily and possibly. If I say giraffe is necessarily animal, is necessarily functioning as an adverb that modifies the whole proposition, or does it only modify the predicate, so that I am ascribing to giraffe the property of necessarily being an animal? That might seem like a pointless question, but it is actually crucial. If necessarily is attached to the predicate and not the copula, then the proposition as a whole is being asserted as merely true, and not as a necessary truth. In which case I won't be able to use this premise in an argument to prove other necessary truths, because you can't infer a necessary truth from a mere truth. In this case, the terminus held that the necessity does apply to the whole proposition. It's perhaps not surprising that a word like necessarily would give rise to such difficulties, but the terminus found that even the copula needed careful thought. Bill Clinton was right, it isn't so obvious what the meaning of the word is is. If I say giraffe is animal, does that refer to some one existing giraffe like Hiawatha who is an animal? Does it mean that all the presently existing giraffes are animals? Does it mean that all past, present, and future giraffes are animals? Or perhaps even that there is a conceptual connection between giraffe and animal, such that my claim would be true even if there are never any giraffes? You can pose more or less the same question as one that concerns the apparently more straightforward categorimatic terms. What exactly is the function of a single term, like giraffe? Does it allude to one specific giraffe I have in mind, like Hiawatha? Or to all the giraffes that exist? To the ones that exist now or also in the past and future? Or could it refer even to possible but never really existing giraffes, like Hiawatha's sister who often features as an example in my non-existent sisters non-existent philosophy podcast? In fact, it seems clear that one and the same term giraffe can function in all of these ways. For this reason, the terminus distinguished between what a term means and how it functions in a given proposition. They called its general meaning its signification. Following suggestive remarks in Aristotle, signification was defined with reference to communication between a speaker and a listener. The signification of a term giraffe is either the concept in my mind that I'm trying to convey to you when I say giraffe, or it is the concept that arises in your mind when you hear me say it. The concepts in our minds in turn signify things out in the world, for instance Hiawatha in the giraffe enclosure. But as we've just seen, I don't need to have any particular giraffe in mind when I say giraffe is animal. So the terminus devised a theory about what they called supposition. A term supposits for whatever it stands for in a given proposition. So the term giraffe has only one signification, but many possible suppositions. No ingenuity was spared in distinguishing a supposition into its types and subtypes. Most generally, the terminus recognized three types, which were called personal, simple, and material supposition. Personal supposition is when a term supposits for a thing or things in the world. Despite the name, the thing doesn't need to be a person. The word tower might, for instance, supposit for the Eiffel Tower or the Leaning Tower of Pisa, which do both have a lot of personality as towers go, but still aren't persons. Our authors further distinguish between types of personal supposition in order to clarify which giraffes I am referring to when I say giraffe. I can, for instance, use the word to refer only to one giraffe, like Hiawatha, and then I am using discrete supposition. Equally, I can use the same term to refer to all giraffes, which is distributive supposition. What if I am not referring to any giraffes in particular, but just to the basic concept of giraffe? In that case, I am using what the terminus called simple supposition. William of Sherwood's example is, human is a species. Obviously, this isn't a case of personal supposition at all, since it isn't as if Bill Clinton or any other human is a species. In addition to personal and simple supposition, the third and final type is illustrated by propositions like, human has five letters. Here I am referring neither to particular humans nor to the species human, but to the word itself. The terminus expressed this by saying that I am engaging in neither personal nor simple supposition but material supposition. What's the point of all this? Most basically, the terminus are trying to keep track of what we are and are not committing ourselves to when we say things. An important benefit of this is that we can thereby avoid making fallacious inferences. As they again spared no ingenuity in pointing out, many fallacies are invalid because they use the same term twice, but with two different kinds of supposition. This was something already recognized in antiquity, albeit with much less systematic rigor. For example, Augustine warned against the following tricky argument, You are human. Human is made up of two syllables. Therefore, you are made up of two syllables. This would be an example of a fallacy that arises because one moves from personal supposition to material supposition. The first premise is about you, the second premise about the word human. In this case, spotting the mistake is pretty easy, but the terminus explored more difficult cases too. For instance, how can it be true to say, Pepper is sold here and in Rome, if there is no particular peppercorn that is sold in both Munich, where I am now, and in Rome? Various solutions were offered here, for instance, by saying that the proposition involves a special kind of unfixed, simple supposition. But supposition theory wasn't only a tool for avoiding mistakes. It also provided a context for arguing over numerous important philosophical issues. For example, we can now recast the problem of universals as one about the supposition of terms. If I say, red is a color, what is the term red suppositing for, and why is my statement true? It is tempting to say that red here has simple supposition and thus refers to the universal red. The reason it is true is that the universal red is a real thing and is a color. Of course, this interpretation would be unacceptable to those thinkers who, in the tradition of Peter Abelard, insisted that nothing real can be universal. Thus in the 14th century, the nominalist John Buridan is going to argue against distinguishing simple and material supposition. Since the universal is actually just a name, saying something like human is a species or red is a color is actually a statement about the word human or the word red. The work of the terminus also raised problems that belong to what we would nowadays call philosophy of language. Take for instance the question of how a term comes to have the supposition that it has. A novel and philosophically exciting feature of the terminus theory is that a term's supposition is a function of the proposition in which that term appears. Adding syn-categorimatic terms can change the supposition of the term. Imagine for instance that I take the proposition, giraffes are tall, and add the word always to get giraffes are always tall. I thereby extend the scope of, or as the medievals said, ampliate, the term giraffes, so that it supposits for the giraffes that exist in the past and future, and not just for the ones that exist now. On the other hand, if I add the word blue and say blue giraffes are tall, I restrict the term giraffes to only those giraffes that are blue. The reason this is exciting is that it suggests a general theory about language. What determines the supposition of a term is its context. There was in fact debate about this suggestion in the 13th century. Some logicians, especially in Oxford, thought that supposition was indeed a function of context. Others, especially in Paris, held that each term has a natural supposition all by itself, which can be altered by its context to produce what they called accidental supposition. A final thing to note about logic in the first half of the 13th century is that despite their focus on terms and predications, these authors realized that their logic needed to go beyond what they could find in Aristotle. Here there is indirect influence from Stoic logic, mostly via Boethius. The Stoics had not added much to Aristotle's pioneering work on categorical syllogisms, but had explored other kinds of inferences, for instance those involving if-then statements. Just like the late ancient Aristotelians, the medieval logicians were loathe to admit that Aristotle had dropped the ball when it came to these inferences. Instead they tried to show how Aristotelian logic could be extended to handle them, thinking of something like an if-then statement as a molecular proposition made up of two atomic statements, both of which are predications. An example might be, if Hiawatha is a giraffe, then she is tall. Here the if and then simply link two predications. This can be handled easily enough within the terminus system by treating if and then as syn-categorimatic terms, and then giving appropriate truth conditions for the molecular propositions that involve them. They did something similar, with the more basic problem of propositions that seemed to involve no predication at all. A statement like Hiawatha runs would be analyzed as a concealed, predicative statement. Hiawatha is running. We ourselves are now running out of time. Indeed, given the topic of this episode, you might say that we are like a US president in his 8th year, coming up against term limits. So I'm going to leave it there for now, but with a promise more reliable than you'd hear in any political campaign, we have much more to expect from medieval logic. And 13th century philosophy can stake a claim to achievements in a broad range of other philosophical areas too, a claim that is, unlike Bill Clinton, unimpeachable. Elect to join me next time as we continue our campaign with a discussion of the impact of Aristotle's physics on medieval natural philosophy, here on The History of Philosophy, without any gaps.