METAPHYSICS. The Problem of Free Will

Transcription

1 METAPHYSICS The Problem of Free Will

2 WHAT IS FREEDOM? surface freedom Being able to do what you want Being free to act, and choose, as you will BUT: what if what you will is not under your control? free will Being an agent capable of influencing the world Source of ones own actions Actions and choices are up-to-us

3 WHY IS FREEDOM IMPORTANT? We feel that we are free; that we are the originators of our own actions We need to be free in order to be responsible for our actions; our practices of praise and blame presuppose that we are free Greene Paper neuroscience, moral and legal responsibility, theories of punishment Roper v. Simmons, 2005, US Supreme Court, unconstitutional to impose capital punishment for crimes committed under age 1 8 Recent scientific advances in brain research indicate that the adolescent brain has not yet fully developed, the decision-making capacity and risk-taking behavior of adolescents are far different from those of adults; thus adolescent offenders are less culpable. Roper v. Simmons: The Role of the Science Brief

4 SOCIETY AND FREE WILL psychological capacities to control our own lives, change our habits and traits, overcome addictions, exercise willpower, and consciously consider the sort of life we want to lead (and to control our behavior accordingly). If people interpret free will to include these sorts of capacities, then telling them that they don t have free will could have detrimental effects on their self-conception, interpersonal relations, and moral behavior, as well as our political debates and legal practices. It may make them more fatalistic, less likely to exert those powers of rational deliberation and willpower they do have, and less motivated to improve themselves and their lives Eddy Nahmias

5 PRINCIPLE OF ALTERNATIVE POSSIBILITIES In 1969 Harry Frankfurt defined what he called "The Principle of Alternate Possibilities" or PAP. "a person is morally responsible for what he has done only if he could have done otherwise. Although I came to class today, I could have decided not to What does the world have to be like for this counterfactual to be true?

6 CAUSAL DETERMINISM (Roughly): the view that the state of the world at a given time determines the state of the world at the next moment Every event that occurs, including human action, is entirely the result of earlier causes [event causation]

7 LAPLACE S DEMON (1814) We may regard the present state of the universe as the effect of its past and the cause of its future. An intellect which at a certain moment would know all forces that set nature in motion, and all positions of all items of which nature is composed, if this intellect were also vast enough to submit these data to analysis, it would embrace in a single formula the movements of the greatest bodies of the universe and those of the tiniest atom; for such an intellect nothing would be uncertain and the future just like the past would be present before its eyes. Pierre Simon Laplace, A Philosophical Essay on Probabilities [3]

8 LAPLACIAN DETERMINISM O set of physical magnitudes, each of which takes a determinate value at every moment of time A history H is a map from R to tuples of values of the basic magnitudes, where for any t in R the state H(t) gives a snapshot of behavior of the basic magnitudes at time t. The world is Laplacian deterministic with respect to O just in case for any pair of histories H 1, H 2 satisfying the laws of physics, if H 1 (t) = H 2 (t) for some t, then H 1 (t) = H 2 (t) for all t. John Earman, Aspects of Determinism in Modern Physics

9 Neuroscientists Complete Fully Mechanistic Explanation of Human Behavior February 20, 2049 By Eddy Nahmias Neuroscientists at the University of Chicago and Georgia State University have found evidence that explains exactly how all human decisions and actions are entirely caused by neurobiological activity. They report that whenever we are trying to decide what to do, the decision we end up making is completely caused by the specific chemical reactions and neural processes occurring in These neuroscientists have shown that once specific chemical reactions and neural processes occur in a person s brain, they will inevitably cause the person to make the specific decision he or she makes. As noted scholar Francis Crick says, Your sense of personal identity and free will are in fact no more than the behavior of a vast assembly of nerve cells and their associated molecules. You re nothing but a pack of neurons. Said Paul Katz, one of the lead researchers, There is certainly no room left for a soul now. There is nothing left for a soul to explain.

10 DETERMINISM: TYPES Causal determinism* Theological determinism Psychological determinism Sociological determinism Biological determinism Environmental determinism

11 COMPATIBILITY? This raises two big questions 1. The determinist question - is determinism true or false? 2. The compatibility question - is free will compatible with determinism? The combination of answers that can be given form the standard positions in the debate

12 POSITIONS IN THE FREE WILL DEBATE D I AG R A M TA K E N F R O M H T T P : / / E N. W I K I P E D I A. O RG / W I K I / F R E E _ W I L L

13 INCOMPATIBILISM Incompatibilists believe freedom is not compatible with determinism; if determinism is true, then one cannot be held truly free and responsible for one s actions Incompatibilists may be divided into two groups

14 INCOMPATIBILISM: HARD DETERMINISM a) Free will is not compatible with determinism b) Determinism is true c) So, we do not have free will HARD DETERMINISTS are incompatibilists who hold that determinism is true

15 INCOMPATIBILISM: LIBERTARIANISM Libertarians believe a) We do have free will b) Free will is not compatible with determinism c) Determinism is therefore false

16 COMPATIBILISM COMPATIBILISTS believe that freedom and responsibility are in every significant sense compatible with determinism; thus there is no conflict between determinism and free will SOFT DETERMINISTS are compatibilists who believe determinism is true Classical Compatibilists: Hobbes, Hume, Mill Modern Compatibilists: Ayer, Dennett, Frankfurt

17 HARD DETERMINISM a) Free will is not compatible with determinism b) Determinism is true c) Therefore, free will is an illusion Support?

18 HARD DETERMINISM CONSEQUENCE ARGUMENT (informal) If determinism is true, then our acts are the consequences of the laws of nature and events in the remote past. But it is not up to us what went on before we were born, and neither is it up to us what the laws of nature are. Therefore the consequences of these things (including our present acts) are not up to us. Peter van Inwagen, An Essay on Free Will (p. 56)

19 HARD DETERMINISM Problems: How can the HD explain our behaviour of praising and blaming agents for their actions, and ascribing responsibility? What happens to morality? If nobody can ever do otherwise than they in fact do, then notions of responsibility, desert, praise, and blame are redundant.

20 a) Determinism is true b) Free will exists SOFT DETERMINISM (COMPATIBILISM) c) There is no tension between these claims If some people see a tension here, it is because they are misunderstanding the notions of freedom and determinism, of free-choice and causal necessity

21 CHALLENGE FOR THE COMPATIBILIST: Incompatibilists say: For our actions to be free, it must be the case that, when we act, we could do otherwise than we actually do This insistence on the ability to do otherwise is often referred to as the principle of alternate possibilities

22 COMPATIBILIST RESPONSES: 1. Interpret the CDO-condition of freedom as having a hypothetical or conditional meaning, i.e. To say one could have done otherwise is to say that one would have done otherwise had things been different (given a different set of beliefs, desires, etc.) [classical compatibilist response]

23 COMPATIBILIST RESPONSES: 2. So what if I couldn t do otherwise? The ability to do otherwise is not in fact required for moral responsibility, and so determinism is no threat to free will 3. The proper contrast to freedom is not determinism, but constraint/coercion As long as we are not constrained, coerced or forced in our actions then we do what we will, and it doesn t matter whether our wills are determined or not

24 FRANKFURT Donald is a Democrat and is likely to vote for the Democrats; in fact, only in one particular circumstance will he not: that is, if he thinks about the prospects of immediate American defeat in Iraq just prior to voting. Ms White, a representative of the Democratic Party, wants to ensure that Donald votes Democratic, so she secretly plants a device in Donald's head that, if activated, will force him to vote Democratic. Not wishing to reveal her presence unnecessarily, Ms White plans to activate the device only if Donald thinks about the Iraq War prior to voting. As things happen, Donald does not think about Iraq prior to voting, so Ms White thus sees no reason to activate the device, and Donald votes Democratic of his own accord. Apparently, Donald is responsible for voting Democratic although, owing to Ms. White's device, he lacks freedom to do otherwise.

25 COMPATIBILISM: PROBLEMS compatibilist freedom is only surface freedom - it is not free will in the full, proper sense Compatibilism is a wretched subterfuge (Kant), a quagmire of evasion (William James)

26 LIBERTARIAN (FREE WILL) POSITION Libertarians believe a) Free will is not compatible with determinism b) Free will exists c) Determinism is therefore false Support? Criticism?

27 DOES INDETERMINISM HELP? Would you be willing to spend a day letting randomness govern your actions?

28 LIBERTARIAN (FREE WILL) More serious problem: POSITION If determinism is false, then events are not subject to chain of cause-and-effect So events occur randomly, by chance (indeterminism) If events occur by chance, then they are not under our control So, how can we be free and responsible?

29 LIBERTARIAN (FREE WILL) POSITION This is known as the Intelligibility Question - how do we make sense of a non-determined free will? 3 common responses: Agent-causal theory (self-determination) Simple indeterminism Causal indeterminism

30 AGENT CAUSATION Not only events can be causes; agents themselves can be causes too (distinction between event-causation and agentcausation) Agent-causation is not reducible to causation by events (agent-causes are not explainable by reference to other events) A STAFF MOVES A STONE, AND IS MOVED BY A HAND, WHICH IS MOVED BY A MAN - Aristotle, Physics 256a

31 AGENT CAUSATION Problems: Many people, including many libertarians, find the notion of agent-causation far too mysterious and problematic Requires agents to be the uncaused cause of their actions, to be prime movers unmoved Problem of economy - positing a second, additional, category of causation

32 1. IS DETERMINISM TRUE? 2. CAN THERE BE FREE WILL? Determinists 1. YES 2. Depends Compatibilists (Soft Determinists) 2. YES Hard Determinists 2. NO Libertarians 1. NO (since FW exists) 2. YES