section_path: Western philosophy/Incompatibilism
section_name: Incompatibilism
paragraph_text: Incompatibilism
  
  Incompatibilism is the position that free will and determinism are logically incompatible, and that the major question regarding whether or not people have free will is thus whether or not their actions are determined. "Hard determinists", such as d'Holbach, are those incompatibilists who accept determinism and reject free will. In contrast, " metaphysical libertarians ", such as Thomas Reid, Peter van Inwagen, and Robert Kane, are those incompatibilists who accept free will and deny determinism, holding the view that some form of indeterminism is true. Another view is that of hard incompatibilists, which state that free will is incompatible with both determinism and indeterminism.
  
  Traditional arguments for incompatibilism are based on an " intuition pump ": if a person is like other mechanical things that are determined in their behavior such as a wind-up toy, a billiard ball, a puppet, or a robot, then people must not have free will. This argument has been rejected by compatibilists such as Daniel Dennett on the grounds that, even if humans have something in common with these things, it remains possible and plausible that we are different from such objects in important ways.
  
  Another argument for incompatibilism is that of the "causal chain". Incompatibilism is key to the idealist theory of free will. Most incompatibilists reject the idea that freedom of action consists simply in "voluntary" behavior. They insist, rather, that free will means that someone must be the "ultimate" or "originating" cause of his actions. They must be causa sui, in the traditional phrase. Being responsible for one's choices is the first cause of those choices, where first cause means that there is no antecedent cause of that cause. The argument, then, is that if a person has free will, then they are the ultimate cause of their actions. If determinism is true, then all of a person's choices are caused by events and facts outside their control. So, if everything someone does is caused by events and facts outside their control, then they cannot be the ultimate cause of their actions. Therefore, they cannot have free will. This argument has also been challenged by various compatibilist philosophers.
  
  A third argument for incompatibilism was formulated by Carl Ginet in the 1960s and has received much attention in the modern literature. The simplified argument runs along these lines: if determinism is true, then we have no control over the events of the past that determined our present state and no control over the laws of nature. Since we can have no control over these matters, we also can have no control over the consequences of them. Since our present choices and acts, under determinism, are the necessary consequences of the past and the laws of nature, then we have no control over them and, hence, no free will. This is called the consequence argument. Peter van Inwagen remarks that C.D. Broad had a version of the consequence argument as early as the 1930s.
  
  The difficulty of this argument for some compatibilists lies in the fact that it entails the impossibility that one could have chosen other than one has. For example, if Jane is a compatibilist and she has just sat down on the sofa, then she is committed to the claim that she could have remained standing, if she had so desired. But it follows from the consequence argument that, if Jane had remained standing, she would have either generated a contradiction, violated the laws of nature or changed the past. Hence, compatibilists are committed to the existence of "incredible abilities", according to Ginet and van Inwagen. One response to this argument is that it equivocates on the notions of abilities and necessities, or that the free will evoked to make any given choice is really an illusion and the choice had been made all along, oblivious to its "decider". David Lewis suggests that compatibilists are only committed to the ability to do something otherwise if different circumstances had actually obtained in the past.
  
  Using T, F for "true" and "false" and ? for undecided, there are exactly nine positions regarding determinism/free will that consist of any two of these three possibilities:
  
  Incompatibilism may occupy any of the nine positions except (5), (8) or (3), which last corresponds to soft determinism. Position (1) is hard determinism, and position (2) is libertarianism. The position (1) of hard determinism adds to the table the contention that D implies FW is untrue, and the position (2) of libertarianism adds the contention that FW implies D is untrue. Position (9) may be called hard incompatibilism if one interprets ? as meaning both concepts are of dubious value. Compatibilism itself may occupy any of the nine positions, that is, there is no logical contradiction between determinism and free will, and either or both may be true or false in principle. However, the most common meaning attached to compatibilism is that some form of determinism is true and yet we have some form of free will, position (3).
  
  Alex Rosenberg makes an extrapolation of physical determinism as inferred on the macroscopic scale by the behaviour of a set of dominoes to neural activity in the brain where; "If the brain is nothing but a complex physical object whose states are as much governed by physical laws as any other physical object, then what goes on in our heads is as fixed and determined by prior events as what goes on when one domino topples another in a long row of them." Physical determinism is currently disputed by prominent interpretations of quantum mechanics, and while not necessarily representative of intrinsic indeterminism in nature, fundamental limits of precision in measurement are inherent in the uncertainty principle. The relevance of such prospective indeterminate activity to free will is, however, contested, even when chaos theory is introduced to magnify the effects of such microscopic events.
  
  Below these positions are examined in more detail.