This is the accepted manuscript of a book review that appeared in Philosophy 90 (2), pp. 332336, in 2015. Review of The Intellectual Powers: A Study of Human Nature by P.M.S. Hacker (WileyBlackwell, Oxford, 2013) This book is the second of an ambitious trilogy on human nature, in which Peter Hacker continues to express his thoughts on a wide range of issues after a long career in philosophy. In volume 1, Hacker explored some of the most general 'categorial' concepts in terms of which we understand ourselves and our world, including substance, causation, agency, and person. In this volume, the concern narrows to the psychological with a focus on our cognitive and cogitative concepts (Volume 3 will focus on our 'moral powers' (xii)). Methodologically, Hacker is deeply influenced by Wittgenstein, concerning whom he is one of the world's foremost scholars and standard-bearers. Accordingly, his aim in this book is conceptual clarification through paying close attention to how the terms expressing those concepts are used, for the sake of dissolving and deflating philosophical puzzles and 'mysteries', correcting error, unmasking nonsense, and vanquishing conceptual confusion. It is striking, however, how differently Hacker's work reads from Wittgenstein's. Whereas Wittgenstein wrote in an aphoristic style of piecemeal reflection, Hacker writes much more systematically, giving painstaking, extensive descriptions of aspects of our system of concepts, even using diagrammatic surveys and tables, offering 'an overview of the conceptual landscape' (438). Interestingly, Hacker shows that Wittgenstein wasn't opposed to such work, citing his remark that 'it is not impossible that such a [conceptual] map will sometime get constructed for the regions we are moving in' (450). Hacker's aim is to supply such a map. To this end, he engages in Strawsonian 'connective analysis', which 'consists in describing the manifold logical connections between a given expression (and its cognates) and other expressions with which it is associated, or with which it is likely to be confounded' (2). Most chapters explore a particular phenomenon, and follow a similar format: a historical introduction where appropriate, followed by detailed analysis of the relevant concept, followed by critiques of various philosophical theories in light of the analysis (often accompanied with explanations for why the theories are so tempting). 2 The first 3 chapters deal with consciousness, intentionality, and language, and whether they are marks of the mental (Hacker favours the third). Much ground is covered. Then a detailed discussion over three chapters ensues concerning knowledge, belief, and their relation. Of particular interest here was a nuanced discussion of know-how, after which Hacker concludes that sometimes knowing-how is reducible to knowing-that, but not always, and also a discussion of the relation between knowledge and belief, where he challenges the view that belief is always a component of knowledge. Hacker argues persuasively that beliefs fit into no general category: they are neither feelings, propositional attitudes, dispositions, mental states nor brain states, though they have affinities with some of these. I suspect, however, that his arguments will be found too inconvenient; philosophers often have need for some handy umbrella term with which to cover such things as beliefs, desires, emotions, etc. It's likely that they will continue to use 'mental state' or 'attitude' for this purpose, for want of a better word. The next two chapters are on sensation and perception. Afterwards, two complex and stimulating chapters follow on the difficult topics of memory and thought. Here, Hacker traces many of the puzzles about memory to the, in his view, mistaken idea that remembering is a kind of experience. He also challenges, among other things, the idea that thinking is an activity, and the views that images, words, or concepts are the medium of thought. A chapter then follows on the imagination. The analyses are lucid, illuminating, precisely expressed, and are often surgically meticulous, though some elements here and there may be questioned. A love for the small detail is displayed, and many subtle and easily overlooked distinctions are made, such as the distinction between knowing that such-and-such and knowing the proposition that such-and-such, or between what an experience is like and what the thing experienced is like. Good use is made of effective analogies, and of the technique (used frequently by Ryle) of illuminating a concept by noting which modifiers (adjectives, adverbs etc.) apply to the relevant term and which don't. The book is also quite polemical, with numerous major theories coming in for serious criticism. On the downside, Hacker sometimes interprets the theories he criticises uncharitably. For instance, he seems to interpret 'condition' in the truth-condition theory of meaning in a causal sense (133-134), rendering the view clearly absurd, when it is surely intended in a constitutive sense (i.e., the sense it takes when philosophers talk of 'necessary and sufficient conditions'). Moreover, when discussing 'the thought that all perception is sensation involving' (275), he 3 interprets 'sensation' in the ordinary sense, and easily disposes of this idea. But 'sensation' is surely intended in a special sense here. It is intended to mean that which is left over in perceptual experience when we abstract away cognition, or the subject's understanding of or judgment about what he's experiencing. It is the component of experience which we have simply in virtue of having functioning sense-organs which are being stimulated. If there is something fishy about this idea, Hacker doesn't show what it is. Similar points may be made about his discussion of the causal theory of perception. For someone who makes frequent philosophical appeal to what we would/wouldn't say, more attention could also have been given to issues of conversational implicature, as once or twice alternative Gricean explanations seemed available for the facts he adduces. For instance, when criticising the idea that knowledge entails belief, Hacker notes that often, when someone knows that p, it 'would be wrong' to report that he believes that p, since this would 'clearly imply that he does not know' it (244-245). Does that mean that knowledge and belief are distinct? That may depend on whether this implication is an entailment or a conversational implicature. Hacker dismisses the latter option without saying why, but a plausible Gricean explanation of the impropriety seems available, which assumes that knowledge is a kind of belief. As Grice noted, there is a conversational expectation that we make our contribution as informative as is required (the Maxim of Quantity)1. By hypothesis, if our subject knows that p then, ipso facto, he believes that p. But the report that he knows that p is more informative than the report that he believes that p (it says the latter plus more). Thus if it's believed that I know all the relevant facts, and I only report that he believes that p, although true (by hypothesis), my audience will assume that he doesn't know that p, since I should have said so if he does. Thus this issue merits further investigation, perhaps by applying Grice's cancelability test etc. The book finishes with a long appendix on philosophical method and metaphilosophy, where Hacker expands on reflections started in volume 1, and makes some important points. He claims that to explicate our concepts, we must look at word usage, since concepts, he holds, are abstractions from the uses of words (384). He is at pains to emphasise, however, that this interest in words and concepts is no less an interest in the natures of things. Philosophical investigation 'elucidates a given concept by describing the use of the word that expresses that concept' (459). Moreover, 'The nature of something consists in those features without which it would not be the 1 Paul Grice, Studies in the Ways of Words (Harvard University Press, 1991, 26). 4 thing it is, and without which it would not fall under the concept that it does. Hence, to clarify a concept is to clarify the nature of what falls under it' (453). Hacker explains (as Carnap did, though awkwardly2) that philosophical discussion can be carried out in different modes, though we often flit between them: the linguistic, conceptual, or the material/necessitarian mode (370 & 446). To illustrate with a simple example, we may ask 'What does "bachelor" mean?', 'What's the concept of a bachelor?', or 'What's a bachelor?' But despite appearances, these questions are not about different things as such (word, concept, and thing respectively), since the answer to one gives the answer to the others. For if 'bachelor' means 'unmarried man', then the concept of a bachelor is the concept of an unmarried man, and furthermore, a bachelor is an unmarried man. And why should we privilege one mode over the others? The Linguistic Turn did not herald a change in subject-matter for philosophy, but only a clearer recognition that answering traditional philosophical questions articulated in the material mode requires paying attention to language. But how are we to know what an expression's proper use is? Hacker rejects two answers which have been offered in recent philosophy: that we should conduct surveys to find out what people say, and that we may rely on our own 'intuitions': 'A competent speaker of the language is by definition someone who knows how to use a wide range of the common non-technical words of the language ... he no more needs to consult others than a competent chess-player needs to ask others how to move the chess-pieces ... he does not need to consult "intuitions" either' (454). Or as he said in volume 1, we 'at most need to be reminded of the familiar'3. The analogy between the rules of language and of chess has its limits. Chess rules are learned explicitly and give clear guidance for all the (formally limited) states of affairs which can arise in chess. The situation with the 'rules' of language is more complex. Consider the method– of no small importance in philosophy–of using thought-experiments to investigate concepts by considering what we would say in some scenario, and note that the scenarios are often highly unusual or even physically/technically impossible. Consider a down-to-earth example: a Gettier case. Smith looks at his previously-reliable watch and comes to believe, at 2pm, that it's 2pm. Little does he know that his watch stopped at 2am last night. Does Smith know that it's 2pm? Here we can't simply recall what is generally said in these and similar situations, because we may never have encountered them, and they are curiously different from what we are familiar 2 Rudolf Carnap, The Logical Syntax of Language (Routledge & Kegan Paul, 1937). 3 P.M.S. Hacker, Human Nature: The Categorial Framework (Blackwell 2007, 14). 5 with. We are left to judge for ourselves whether knowledge extends to this case. Given its novelty, we can't simply recall what we actually say in such situations ('marshal what one already knows', 454), but must judge what we would or should say (the question of what determines these judgments is an important one). These judgments are then called 'linguistic intuitions'. Is this so inappropriate? Nevertheless, Hacker's conception of philosophy as a sui generis, a priori exercise in conceptual clarification restores to philosophy a dignity that has often seemed under threat from recent conceptions of it which blur the line between philosophy and science. But it also seems overly narrow. It is unclear, for instance, whether conceptual clarification is the panacea for all the problems and concerns which arise across sub-disciplines such as logic (formal and informal), philosophy of religion, science, and history, let alone ethics, political philosophy, philosophy of education, and Eastern philosophy, where thinkers are often concerned with normative and practical questions of what it's right to do, how we should arrange society, how we should live, and what is of value. Naturally enough, there is plenty of overlap between this book's content and other works in Hacker's large corpus, but also much that is new, with significant expansions on issues previously covered. After reading its chapters one is often left feeling as though the air has been cleared in what was a musty, stuffy room. It should be recommended to anyone interested in the topics it covers. Kevin Lynch