Fatalism and free will

For Jan Łukasiewicz logical determinism as presented in the previous lecture was unacceptable. He insisted that the fault lies in the logic that underlies the argument. Łukasiewicz claimed that in order to reject logical determinism we have to abandon classical logic and two of its fundamental principles: the principle of the excluded middle and the closely related principle of bivalence, stating that each grammatically and semantically correct sentence has one of the two logical values: truth or falsity. Łukasiewicz introduced a new, three-valued logic, in which any sentence can receive one of the three values: truth, falsity, and indeterminacy (‘possibility’). If we believe that the fact that it will rain tomorrow is not determined today, we should assign to the statement “It will rain tomorrow in Warsaw” the third logical value of indeterminacy. Łukasiewicz’s logic has a rule, according to which the disjunction of two indeterminate sentences is itself indeterminate. So the sentence “It will rain tomorrow in Warsaw or it won’t rain tomorrow in Warsaw” is neither true nor false today, and the principle of the excluded middle is not valid.

But it may be pointed out that the afore-mentioned disjunction will for certain turn out to be true, no matter what the weather will be like in Warsaw on the next day. So Łukasiewicz’s conception has an important flaw: under his interpretation a sentence about the future which for certain will receive the value “true” has to be deemed indeterminate at present. (Moreover, in Łukasiewicz’s logic it is possible to construct a sentence which is true now but it will turn out to be false in the future!) One possible way of ameliorating this situation is to cut off the link between the truth of the disjunction as a whole, and the truth of its components. We can admit that the whole disjunction “It will be p or it won’t be p” is true now, but from this it doesn’t follow that p is true now or not-p is true. The conclusion only follows if we accept the principle of bivalence, but if we admit that there is a third logical value, the argument is no longer valid. So an alternative proposal is to retain all the laws of classical logic but to extend the number of logical values to three instead of two. But one consequence of this strategy is that classical connectives will no longer be truth-functional. Compare the statement “Tomorrow it will rain or tomorrow it won’t rain” with the disjunction “Tomorrow I will write a letter or visit my friend”. Under the assumption that all sentences involved are indeterminate as of now, the first disjunction comes out true, but the second is indeterminate (it can still happen that I won’t write a letter and I won’t visit my friend).

Finally, it may be claimed that logical determinism has nothing to do with genuine determinism, and that it is based on some sort of semantic confusion. When I say that it is true at t1 that x happens at t2, it looks like I am reporting a fact of the matter which happens at t1, but actually the fact I am talking about still takes place at t2. Hence, if I say that today it is true that tomorrow it will rain, semantically it is the same as if I said simply “Tomorrow it will rain”. I am talking about a future event which exists in a different temporal sphere from the moment of my utterance (this reminds us of the eternalist conception of time).

Logical determinism is closely related to another philosophical position known as fatalism. Fatalism stresses that there is only one possible scenario which the universe will follow in its future development, and therefore any action we may want to take is futile: it will be what is supposed to be regardless. One popular version of fatalism is religious (theological) fatalism. God is omniscient (all-knowing), and therefore he knows everything about the future as well as about the past. From this it seems to follow that he knows what will happen with me regardless of my actions. Logical fatalism, in turn, is based on a similar argument to the argument for logical determinism. The principle of the excluded middle ensures that every statement about the future is already either true or false, so it looks like our current actions are superfluous. Fatalism implies that we are actually not creators of our destiny – that whatever we do does not make any difference for our future.

A typical argument supporting logical fatalism can be presented as follows. It doesn’t make sense to take any precautions, for instance to take shelter during an air raid, because it is true that either you’ll be hurt in the bombing or you won’t (again, we assume the principle of the excluded middle). If you are going to be hurt, no precautions can help (they will turn out to be ineffective), whereas if you are not going to be hurt, precautions are unnecessary. Thus it is not rational to take any precautions. This argument has a similar structure to a more plausible argument showing that present actions are irrelevant to the past events of which we don’t know yet. As the argument goes, it is pointless to pray for the survival of a friend in a catastrophe which happened yesterday when the full list of victims is not yet known, because again either the friend survived or he didn’t. If he survived, the prayer is not needed, whereas if he died, it is futile.

But there is an important difference between the two cases. The present actions can causally influence future events, but not the past ones. It is not true that if I am not going to be hurt in an air raid, my actions will turn out to be irrelevant to this outcome. The relevance of a given action can be evaluated with the help of counterfactual conditionals only: we have to assess what would happen, had I not done what I actually did. Suppose, for instance, that I met a friend on my morning walk. I can’t say that my decision to go on a walk this morning was irrelevant to this fact: if I hadn’t gone for a walk, I would not have met my friend. Regarding the theological version of fatalism, it may be objected that God’s foreknowledge about our future actions does not preclude the fact that these actions are free. It is not the case that I am choosing to do X now because God knew that I would do X, but rather God knew this because of my current decision. I could make a different decision, but this would not confute God’s knowledge; rather it would change his knowledge. (Of course one controversial issue remains: it looks like my action can influence the past.)

It may be noted that fatalism effectively denies the existence of free will. But we can ask whether physical determinism has the same consequence. So the next issue we are going to consider is whether determinism is logically compatible with free will. There are several positions regarding this issue. Compatibilism states that determinism can be logically reconciled with the existence of free will, whereas incompatibilism professes that determinism logically excludes free will. Incompatibilism is further divided into two positions: libertarianism, which asserts that free will exists and therefore determinism must be false, and hard determinism, assuming the universal validity of determinism and denying that people have free will. On the other hand, a typical variant of compatibilism is the position known as soft determinism, which accepts both determinism and free will. Of course it is logically possible to be a compatibilist and to deny determinism or free will, or even both. For instance, some philosophers subscribe to compatibilism while maintaining that in fact determinism is false in our world and free will exists. Such a position could be called “soft libertarianism”.

Reading regarding fatalism and free will

B. Garrett, Chapter 7 "Free will", pp. 103-112, What is this thing called metaphysics?