22 Are We Free to Break the Laws?
The Consequence Argument puts pressure on the view that determinism is compatible with free will. If determinism is true, then what you do is an inevitable consequence of the past in combination with the laws of nature, which are both well beyond your control. The argument is formulated in terms of a propositional operator:
\[ \begin{array}{lll} NP & : & P, \ \text{and no one has or ever had any choice about whether} \ P\\ \end{array} \]
Since no one has or ever had a choice over the past and the laws of nature, no one has or ever had a choice over what they do, which is a necessary consequence of the combination of both.
But while the Consequence Argument is framed in terms of choice the debate over free will is often framed in terms of ability: an action is free only if the agent could have done otherwise. The two formulations are closely related. If you had no choice over \(P\), then there is nothing you could have done to make \(P\) false, which is to say that you could have not not have done otherwise. Conversely, if you could have not not done otherwise, then there is nothing you could have done to make \(P\) false and you had no choice over \(P\). So, we may regard the no choice operator \(N\) as another way to express the thought that the agent could have not not done otherwise.
(Lewis 1986) defends a compatibilist position framed in terms of ability. His strategy is not to deny that there is nothing we could have done to change the past or to break the laws of nature, but rather to clarify what that is supposed to mean and to explain what type of ability is required for free will. In particular, he frames the debate in terms of what we are able to render false: we can ask, of a given proposition, whether there is something we are able to do such that, if we did it, that proposition would be false.
The final take is that the Consequence Argument derives much of its force from an equivocation between two different interpretations of ‘could have done otherwise’. Once they are properly distinguished, there is a principled compatibilist response to the argument.
One freely does what is predetermined to do, since one can act otherwise even if one’s act is determined by the combination of the past and the laws of nature.
Compatibilism is, for Lewis, the thesis that soft determinism may be true.
22.1 The Compatibilist’s Dilemma
Suppose determinism is true and I raise my hand at a given time. Consider the alternative: I do not raise my hand and put it back on the table instead. If determinism is true, the fact that I raise my hand is determined by the combination of the past and the laws of nature. For my act to raise my hand to be free, it must be the case that I could have done otherwise. But given determinism, if I had not raised my hand, then either:
The laws of nature would have been different, or
The past would have been different.
We have a dilemma. We cannot break the laws of nature, which is what would be required for the first option. Nor can we change the past as we established earlier in the unit. But if neither option is available, the conclusion that we lack free will appears inescapable.
22.2 How to Interpret ‘To Be Able to Break the Laws’
(Lewis 1986) focuses on the first horn of the dilemma:
I am committed to the consequence that if I had done what I was able to do—raise my hand—then some law would have been broken.
“That is to say,” my opponent paraphrases, “you claim to be able to break the very laws of nature. And with so little effort! A marvelous power indeed! Can you also bend spoons?”
The key now is to reject the paraphrase by means of a distinction between two different interpretations of what it means to ‘be able to break the laws’:
Weak Thesis. I’m able to do something such that, if I did it, a law would have been broken.
Strong Thesis. I’m able to break a law.
To appreciate the difference, consider the commonplace ability to break a window. Suppose I did not break a window. I would still be able to throw a stone in a certain direction, and, if I did, the window would break.Then, I would be able to break the window. I’m able to do something such that, if I did, my act would cause a window-breaking event.
Now compare this with an ability to break of the laws of nature. Suppose I’m able to throw a stone very hard, and, if I did, then the stone would fly faster than light, contrary to law. Then I would indeed have an ability to break a law of nature. I would be able to do something such that, if I did, my act would cause a law-breaking event.
(Lewis 1986) agrees that it would be unreasonable to ascribe that sort of power to ordinary agents. But, he argues, compatibilism requires only the weak thesis. Suppose that contrary to fact, I had raised my hand. To be sure, if I had raised my had, the laws of nature would have had to be marginally different, which means that there would have been a departure from the actual laws at some point before I carry out the act. However, this divergence, whatever it may have been, would have not been caused by my act, but rather would have preceded it.
One way to put it is that there is a nearby possible world that matches the actual world up to some time except for a localized violation of the laws of our world and such that at that world I act otherwise: I raise my hand and my act is perfectly consistent with the laws of nature of that world.
(Lewis 1986) argues that compatibilism requires only the weak interpretation of ‘able to break the laws’, not the strong one. We may agree with the incompatibilist that no one is able to break the laws of nature in accordance with the strong thesis, but we should reject the suggestion that something like that would be required for the truth of compatibilism. To claim that I could have raised my hand is not to claim a supernatural ability to break the laws of nature but merely that there is a nearby possible world in which the laws of nature are marginally different, and I raise my hand in that world.
22.3 The Consequence Argument Revisited
Recall a schematic reconstruction of the Consequence Argument. Let \(A\) be the proposition that I do not raise my hand and rest it on the table instead.
If is necessary that if \(H\) and \(L\), then \(A\).
From determinism.
No one is able to render \(H\) and \(L\) false.
Therefore, no one is able to render \(A\) false.
From 1 and 2 by a transfer principle for the ability to render false.
(Lewis 1986) draws a distinction between two interpretations of the ability to render something false.
Two interpretations of the ability to render something false.
Weak Interpretation
I can render a proposition false iff I’m able to do something such that, if I did, the proposition would have been falsified (though not necessarily by my act or by anything caused by my act.)
Strong Interpretation
I can render a proposition false iff I’m able to do something such that, if I did, the proposition would have been falsified by my act itself or by some event caused by my act.
What is the status of the argument for Lewis?
He accepts premise 1, which flows from determinism.
He accepts premise 2 on the strong interpretation of the ability claim:
No one is able to do something such that, if they did, the conjunction of the past and the laws of nature would have been falsified by the act itself or by some event caused by that act.
He rejects premise 2 on the weak interpretation of the ability claim:
I’m able to to something, e.g., raise my hand, and if I did, the conjunction of the past and the laws of nature would have been falsified (though not necessarily by my act or by anything caused by my act.)
Fortunately, the weak interpretation of ability is all that is required to accommodate the compatibility of determinism and free will.