LOGIC ‘Induction’ was a name that had long been given by logicians to the process of deriving a general truth from particular instances But there is more than one kind of induction Suppose I state ‘Peter is a Jew, James is a Jew, John is a Jew ’ and then go on to enumerate all the Apostles I may go on to conclude ‘All the Apostles are Jews’, but if I so, Mill says, I am not really moving from particular to general: the conclusion is merely an abridged notation for the particular facts enunciated in the premiss Matters are very different when we make a generalization on the basis only of an incomplete survey of the items to which it applies—as when we conclude from previous human deaths that all humans of all times will die Mill’s criticism of deductive argument involves a confusion between logic and epistemology An inference may be, as he says, deductively valid without being informative: validity is a necessary but not a sufficient condition for an argument to produce true information But syllogism is not the only form of inference, and there are many valid non-syllogistic arguments (e.g arguments of the form ‘A ¼ B’, ‘B ¼ C’, therefore ‘A ¼ C’) which are quite capable of conveying information Even in the case of syllogism, it is possible to give an account that makes it a real inference if we interpret ‘All men are mortal’ not as saying that ‘mortal’ is a name of every member of the class of men but—in accordance with Mill’s own account of naming—as saying that there is a connection between the attributes connoted by ‘man’ and by ‘mortal’ Mill would no doubt respond by asking how we could ever know such a connection, if not by induction; and the most interesting part of his Logic is his attempt to set out the rules of inductive discovery He set out five rules, or canons, of experimental inquiry to guide researchers in the inductive discovery of causes and effects We may consider as illustrations the first two of these canons The first is called the method of agreement It states that if a phenomenon F appears in the conjunction of the circumstances A, B, and C, and also in the conjunction of the circumstances C, D, and E, then we are to conclude that C, the only common feature, is causally related to F The second, the method of disagreement, states that if F occurs in the presence of A, B, and C, but not in the presence of A, B and D, then we are to conclude that C, the only feature differentiating the two cases, is causally related to F 99