A System of Logic Ratiocinative and Inductive Presenting a Connected View of the Principles of Evidence and the Methods of Scientific Investigation John Stuart Mill Copyright © Jonathan Bennett 2017. All rights reserved [Brackets] enclose editorial explanations. Small ·dots· enclose material that has been added, but can be read as though it were part of the original text. Occasional •bullets, and also indenting of passages that are not quotations, are meant as aids to grasping the structure of a sentence or a thought. Every four-point ellipsis . indicates the omission of a brief passage that seems to present more difficulty than it is worth. In this work such omissions are usually of unneeded further examples or rewordings. Longer omissions are reported between brackets in normal-sized type.—When a word is spoken about in this version, it is usually put between quotation marks; Mill himself does that with phrases and sentences but not with single words.—Mill here refers to contemporaries by their surnames; in the original he is less abrupt—‘Archbishop Whateley’, ‘Professor Bain’, and so on. First launched: June 2012 Contents Introduction . 1 I: Names and propositions 7 Chapter 1: The need to start with an analysis of language . 7 Chapter 2: Names . 9 Chapter 3: Things that are denoted by names . 19 Chapter 4: Propositions . 34 Chapter 5: The import of propositions . 39 Chapter 6: Merely verbal propositions . 48 Chapter 7: The nature of classification. The five predicables. 53 Chapter 8: Definition . 60 Mill’s System of Logic Glossary accidentally: You have your height accidentally, meaning denote: In its root sense this mean ‘stand for’, ‘refer to’—so that your height could have been different without that that ‘mankind’ denotes the human race, your name denotes affecting who you are. you, and so does any description of the form ‘the. ’ that is true of you and nothing else. On page 8, however, we see art: In this work, ‘art’ is a vehicle for several related ideas: Mill stretching the word in two ways: in ‘Abraham Lincoln rules, skill, techniques. was tall’, Mill would say that assertion: Mill uses this in about the way we use ‘proposi- •‘Abraham Lincoln’ denotes Abraham Lincoln; tion’. For there to be an ‘assertion’, in his sense, no person •‘tall’ denotes tallness, and needs to have asserted anything. Mill sometimes speaks of •‘was’ denotes that something is being affirmed of propositions as asserting this or that. something. He doesn’t comment on the vast difference between basic: This replaces Mill’s ‘original’ in some of its occur- ‘x denotes y’ and ‘x denotes that P’. rences. differentiae: Plural of ‘differentia’. begging the question: Mill’s sense of this phrase is the division: classification only sense it had until fairly recently: ‘beg the question’ was to offer a ‘proof’ of P from premises that include P. It now frame: To frame an idea is to form it, cause it to exist in means ‘raise the question’ (‘That begs the question of what your mind; how you frame a proposition or definition has to he was doing on the roof in the first place.’) It seems that do with how you shape it or formulate it. When Mill speaks complacently illiterate journalists (of whom there are many) of framing a class he means forming or creating a class. encountered the phrase, liked it, guessed at its meaning, identical proposition: Strictly speaking, this is a proposi- and plunged ahead without checking. tion of the form ‘x is x’, where the subject and predicate are identical. But the phrase came also to be used for any cardinal: principal, most important, leading. proposition where the meaning of the predicate is a part of co-extensive: Used here in the sense that it still has: when the meaning of the subject. Mill says (page 4) that ‘the field of logic is co-extensive with import: In Mill’s use of it, this means about the same as that of knowledge’ he means that any pursuit of knowledge ‘meaning’; but he does use both those words, and the present will involve issues about logic, and that any study of logic version will follow him in that. will bring in issues about knowledge. induction: At the start of III.2 Mill defines this as ‘the data: Mill’s readers will have understood ‘data’ as the plural operation of the mind by which we infer that what we know of ‘datum’. Many years later it degenerated into a singular to be true in a particular case or cases will be true in all cases mass-term, like ‘soup’. that resemble the former in certain assignable respects.’ Mill’s System of Logic meaning: In most places this is the word Mill has used, but principle: Mill nearly always uses ‘principle’ as you and I do, sometimes it replaces his ‘acceptation’. It sometimes appears to stand for a special kind of proposition. But the word used in the singular though the plural would seem more natural; to have a common meaning, now obsolete, in which ‘principle’ that’s how Mill wrote it. means ‘source’, ‘cause’, ‘driver’, ‘energizer’, or the like; and Mill uses it just twice, in the same paragraph (page 28, in mutatis mutandis: A Latin phrase that is still in current the phrase ‘thinking principle’—meaning ‘whatever it is that use. It means ‘(mutatis) with changes made (mutandis) in drives our mental processes’. the things that need to be changed’. The use of it implies that it’s obvious what the needed changes are. proximate kind: The lowest kind—corresponding to the smallest class—in an Aristotelian classification. See page 56. name: Mill uses ‘name’ in such a way that ‘Bentham’ and ‘gold’ and ‘the author of Spies’ and ‘yellowness’ and ‘yellow’ real: On page 51 the word ‘real’ is tightly tied to its origin are all names. The odd one out is ‘yellow’ but Mill insists in the Latin res = ‘thing’. So the contrast between ‘real’ that it names the same colour that ‘yellowness’ names. In propositions and ‘verbal’ ones involves the contrast between the present version this usage of his will be strictly followed. things and words. noumenon: A Greek word, much used by Kant, meaning science: Any intellectual discipline whose doctrines are are ‘thing considered as it is in its own nature’ in contrast highly organised into a logical structure. It doesn’t have to with ‘thing considered in terms of how it appears’, i.e. phe- involve experiments, or to be empirical. Many philosophers nomenon. The plural is noumena. You’ll see on page 45 thought that theology is a science. that Mill takes it for granted that noumena are the causes of signification: This seems to mean about the same as ‘mean- phenomena. ing’, but Mill uses both words, and this version will respect his choices. popular: Even as late as Mill’s time this mainly meant ‘of the people’, usually the not highly educated or very intelligent summa genera: The plural of summum genus = ‘highest people. It didn’t mean ‘liked by the people’. class’. Mill explains this well enough on page 19. Mill’s System of Logic Introduction Introduction §1. Writers on logic have differed as much in their defi- §2. Logic has often been called ‘the art of reasoning’. Arch- nitions of it as in their handling of its details. This isn’t bishop Whately, the writer who has done most to restore logic surprising in a subject where writers have used the same to the level of esteem which it used to have from educated language to convey different ideas. It’s the same in ethics and people in England, has defined logic as the science and the jurisprudence. Almost every writer, having his own views art of reasoning; meaning about some aspects of these branches of knowledge, has •by ‘science’: the analysis of the mental process that framed his definition in a way that shows beforehand what occurs when we reason, and his particular views are, sometimes begging the question [see •by ‘art’ [see Glossary]: the rules, based on that analysis, Glossary] in their favour. for conducting the process correctly. This diversity is an inevitable result—and to some extent He was certainly right to add ‘the science and’: a system a proper result—of the imperfect state of those sciences of rules governing the process must be based on a grasp of the mental process itself—the steps it consists of and [see Glossary]. You can’t expect people to agree about the definition of anything if they don’t agree about the thing the conditions it depends on. Art requires knowledge; art itself. To define something is to select from its properties the that has grown beyond its infant state requires scientific ones that are to be understood to be declared by its name; knowledge. Not every art bears the name of a science, but and we aren’t competent to make that selection until the that’s because in many cases a single art is based on several thing’s properties are well known to us. And when the ‘thing’ sciences. is as complex as a science, the definition we start with is So logic is the science and art of reasoning. But the seldom one that we’ll still think appropriate when we know word ‘reasoning’—like most scientific terms in popular [see more. Until we know the details we can’t pick the most Glossary] use—is highly ambiguous. In one of its senses it correct and compact way of gathering them under a general means syllogising, i.e.