Draft version. The final version of record of this review is published by Oxford University Press in The Philosophical Quarterly and can be found at: https://academic.oup.com/pq/advance-articleabstract/doi/10.1093/pq/pqz048/5545663?redirectedFrom=fulltext Review of Christian List, Why Free Will is Real Harvard University Press 2019 by Anneli Jefferson The ability to freely choose between different options for action is part of our understanding of ourselves as agents. Yet, there is ongoing debate as to whether we are in fact free to choose, and about what exactly free will consists in. In his engaging yet rigorous new book, Christian List takes on the challenge of defending free will. List argues that there are three conditions that need to be met in order for agents to have free will: they need to be able to act intentionally, there need to be genuinely open possibilities for action, and they need to be able to control their actions. According to List, these requirements are threatened by three challenges: the requirement of intentional action is threatened by the challenge of eliminativism, the requirement of genuinely open possibilities is challenged by determinism, and the requirement of control is threatened by the acceptance of physicalism and the causal exclusion argument. He identifies a common thread running through these three challenges, in that all of them create problems for free will by focusing on the level of the physical system rather than the agential level (p.150). List's defence of intentional action follows well established arguments against the reducibility of intentional explanations to explanations in terms of physiological processes. Following Dennett, Fodor and others, he argues that our best explanations of actions rely on the ascription of intentions, and that because these intentions are physically realised in multiple different ways, the physiological level is not suitable for explaining actions. The naturalistic ontological attitude holds that those entities that the best theory for explaining a phenomenon posits are real entities. If we accept this position, as List urges we should, we should also conclude that because we need intentions to explain actions, they are in fact real. Probably the most controversial and innovative argument of the book is List's defence of indeterminism at the agential level. He labels his position compatibilist libertarianism, and argues that even if we accept determinism at the physical level, there are genuinely open possibilities for the agent at psychological/agential level. Many compatibilists do not require there to be genuinely open possibilities in the sense that an agent's decision is not determined by prior events. Rather, they take it to be sufficient for free will and moral responsibility if agents' decision making processes are causally relevant to the decision reached and the action performed. However, List takes the intuition that free will requires genuinely open possibilities as central to our concept of free will and sets out to defend it. How does this work? List once again makes central use of the concept of supervenience in his argument. If a property A supervenes on another property B, there can be no changes in A without there also being changes in B. However, it is possible that there can be changes in B without there being changes in A, because of multiple realisability. So, in the case of physical properties realising mental states, it is possible for two (or more) different physical states to realize one and the same mental state. This can lead to branchings at the agential level, where more than one outcome is possible given an initial psychological state of decision making – the agent can choose to have coffee or tea even when there can only be one possible sequence of events at the physical level. The reason for this is that what is one and the same state at the psychological level of description can be realised by different underlying physical states. Thus physical states B1 and B2 may both realise mental state A1. Because of determinism at the physical level, B1 and state B2 each only have one possible future outcome, B3 and B4 respectively. However, because B1 and B2 realise the same type of mental state A1, we can end up with A2 (realised by B3) or A3, (realised by B4). This is a very clever and ingenious way of trying to introduce indeterminacy at the agential level. However, the incompatibilist may feel that some sleight of hand has taken place. Why is that? It seems that the indeterminacy that is introduced is only apparent and an artefact of the level of description. It isn't really the case that at the point where an individual is in state A1, there is no fact of the matter as to whether they will be in A2 or A3 next. Rather, we do not know which one it will be when we look at the agential level. But if we were to look at the physical level, and if we were able to translate the physical state into the corresponding mental state, we would know what has to come next. List would agree that physicalism and supervenience together imply that the future is fixed, but would argue that if we take the independence of different levels of explanation seriously, then all the predictive and explanatory action takes place at the level of the mental. The schematic presentation of the supervenience relation may make it look like we could reduce mental state A1 to physical states B1 or B2, but the overall argument of the book is precisely that we can't, and that a picture whereby one mental state can be neatly reduced to one of two distinct physical ones is overly simplistic. The importance of taking the separation of levels of explanation seriously is also central to List's final argument for the causal relevance of mental states and decisions. The worry that List addresses here is that our mental states are mere epiphenomena, which do not do any causal work in our actions, because all the causal work takes place at the physical level. According to the causal exclusion argument, physicalism commits us to there being sufficient causes for action at the physical level, and this leaves no space for mental causes, as this would overdetermine an outcome. List once again argues that due to supervenience relations involving multiple realisability, it is often the higher level that we need to appeal to in order to get explanatory traction. He illustrates this point by using the example of boiling water breaking a bottle. Water boiling can be realised by different microstates of the water molecules, and each of these is sufficient but not necessary for the water boiling and the bottle breaking. The right level of explanation therefore refers to the boiling of the water, not to the ways in which this is realised by the microstates of the molecules. Similarly, the meat in action explanation is at the mental level of explanation, not at the level of physical realisation. List's book is extremely well written and readable, but it covers a lot of very complex material drawing on debates in metaphysics, philosophy of mind and philosophy of science. This makes it very rewarding, and while he may not convince incompatibilists that the problem of combining determinism at the physical level with indeterminism at the agential level is resolved, he presents an intriguing case.