[1] The philosophy of Thomas Reid has undergone a rediscovery during the last couple of years. Various philosophers are re-introducing Reid’s ideas in mainstream philosophical discussions where they can compete with the ideas of more commonly discussed 18th century philosophers such as Kant and Hume. Manifest Activity is an excellent example of how Reid’s ideas can be fruitfully applied to current philosophical debates and, at the same time, it is a thorough work of Reid-scholarship.
[2] The title of Yaffe’s book beautifully characterizes Thomas Reid’s philosophy of action: according to Reid, it is manifest that human beings have active power. Recall that Reid is the founder of the Scottish common sense school. Reid criticizes philosophers such as Hume and Descartes because they question our every day experiences by skeptical philosophical arguments. Instead, Reid thinks that philosophers have to take common sense as their starting point and may only cast our everyday phenomenology into doubt if they have very good reasons to do so. Reid’s work can be seen as a rebellion against revisionistic approaches in philosophy. Of course, Reid’s opponents will be quick to reply that Reid is simply naive and, rather than doing genuine philosophy, Reid just confirms our uninformed prejudices. However, Yaffe’s detailed examination of Reid’s argument proves this view to be wrong and shows that Reid did in fact go through sophisticated philosophical argument to give us a better understanding of what we directly experience through our common sense.
[3] Reid argues against naturalistic accounts which try to reduce human agency to mere physical pushes and pulls. Without active power, we cannot be morally responsible, and yet it is manifest that we do have active power and that we can be morally responsible. Reid thinks that all events in the world are ultimately directed towards ends. End-directedness requires that there are efficient causes, not only physical causes. Only agents can be efficient causes: God, angels and human beings. God is the efficient cause of the lawlike behavior of natural events, while human beings are the efficient causes of their own actions.
[4] In the first chapter of his book, Yaffe offers a detailed discussion of a passage in which Reid states that having active power means being able to exert that power, and being able to exert active power requires will, which in turn requires understanding. In the next chapter, we can read an analysis of Reid’s arguments for the claim that active power to do something means that we must also have the power not to do it; it means power to do one thing rather than another. With these arguments, Reid challenges the idea of some naturalists that determinism is compatible with free action. Strangely, Yaffe argues for the idea that active power means ‘power to do one thing rather than another’ as ‘power to prevent something from happening’ (pp. 49–51). The latter is a much stronger claim and not necessary for Reid’s argument. In any case, Yaffe does not offer an argument to the effect that both claims should be equivalent.
[5] Chapter three, ‘From Change to Power’, discusses Reid’s idea that every event has an efficient cause. Reid claims that we accept this idea non-inferentially and he rejects an argument by Hobbes that is supposed to establish it. Hobbes’s argument is based on the Principle of Sufficient Reason. Yaffe discusses various interpretations on which this principle is either false or identical to the principle of universal efficient causation. For Hume, this is a reason to reject the principle of efficient causation, whereas Reid says that we don’t need an argument for it. However, Yaffe argues that there is a possible interpretation of the Principle of Sufficient Reason on which Hobbes’s argument would work, namely by taking it to mean that every event is end-directed. According to Yaffe, given Reid’s own providentialist views he should endorse this interpretation of Hobbes’s argument. Nevertheless, Yaffe says that this does not need to undermine Reid’s claim that we understand and accept the principle of efficient causation non-inferentially. This is a central feature of Reid’s common sense-methodology: we accept certain propositions as first principles of our reasoning. These can be empirical propositions that we understand directly through our senses and also apriori-propositions that we understand directly through reason. Other propositions can be derived from these first principles through deduction or induction. However, some first principles are justification-wise overdetermined: we can understand them directly and non-inferentially, but it is nevertheless possible to provide a deductive or inductive argument for them. Reid’s reliabilist epistemology allows that even in those cases, we are justified in believing the proposition at stake non-inferentially.
[6] In the fourth chapter, Yaffe focuses on one of three arguments for moral liberty which Reid offers. The argument is that human beings are able to make and execute plans, which requires that human beings are wise, which in turn requires that they have active power. Yaffe states that this argument has rarely been discussed and mainly been dismissed. He attempts to show that this argument can be made to work, namely by looking at what Reid has to say about character traits. Yaffe argues that for Reid the following relations are the same: the relation between character and regularities in behavior, and the relation between the resolution to exert power consistently and regularities in nature. Although it is impossible to prove beyond doubt that regularities in nature are efficiently caused we cannot but think that they are, and the same holds for our conviction that other human beings are endowed with powers and the ability to exert them with regularity.
[7] In chapters five and six, Yaffe discusses which role motives or reasons play in Reid’s philosophy of action. Yaffe attempts to show that for Reid, motives are not causal pushes as the naturalist would have it. Rather, motives are the ends for which we perform actions. In chapter six, Yaffe discusses Reid’s idea that human beings can act contrary to their desires, for example, if they judge an action to be morally right. This is yet another sign of our moral freedom. Here, Yaffe overlooks a certain complexity of Reid’s thought. Even though being an advocate of active power, Reid does not claim that human beings typically act (purely) rationally, and that if they don’t act from rational motives, they act from egoistic desires. Instead, Reid’s account of the moral emotions states that human beings very often do not (only) act according to judgment but according to their feelings. However, Reid thinks that we have pre-rational benevolent affections and rational emotions of approbation and disapprobation that can drive us to do the right thing, and that feelings are better than purely rational states in motivating us. [1]
[8] Yaffe goes through great lengths analyzing Reid’s arguments and the various premises on which they rest. It is impressive how Yaffe is able to connect claims and arguments that Reid offers in various places in his works. However, this is not always equally convincing. In the concluding chapter Yaffe examines whether the commonly accepted view is true that Reid defends agent causation. According to Yaffe, holding such a view entails the danger of regress: in order to have power to act in a way, an agent needs to have power to exert that power. If in turn the power to exert is exercised through exertion, then we end up in a regress. Yaffe offers an alternative explanation, by looking at the notion ‘trying’. If S tries to do A and fails, S did something, namely try. If S tries to do A and succeeds – did she do two things, i.e. 1. try and 2. A? That is not how we commonly think about successful action. Now Yaffe suggests to take a similar approach to exertion, for which he seems to have found evidence in a recently published paper by Reid: [2] ‘In the case of success, the exertion is present, but it is not action; it is not the sort of thing that it is prior to success, or in cases of failure’ (p. 155). With such an account, regress can be avoided: ’If an agent succeeds in acting, then his exertion is no action; it is not something he did or, what’s the same, something he efficiently caused’ (p. 156). Surely, this seems ad hoc. What follows is even more puzzling: ‘However, if he fails, he successfully exerted himself, his exertion to exert, in this case, is not some further action of which he is the cause’ (p. 156). Why should that hold? We still need to understand how it is possible that the agent exerted herself. Having success or not seems irrelevant and is merely an afterthought. Yaffe’s positive point is rather disappointing: ‘But what is exertion in cases of success? The best answer is: who knows?’ (p. 156). This is a very unsatisfactory answer, to say the least, and one that will only confirm the naturalist in his conviction that active power is a dubious concept.
[9] Manifest Activity offers an extremely dense analysis and reconstruction of Reid’s arguments which often makes the book difficult to read. Yaffe’s – in many respects admirable – analytic approach has the drawback of losing the charm of Reid’s often polemical, humorous and entertaining way of writing. Readers of Yaffe’s book should still consult Reid’s own works in order to get a flavor of not only the common sense ideas of Reid but also of his common sense style of writing. In any case, anybody who is interested in Reid’s philosophy of action should read Yaffe’s book.