The Unavoidability Argument for Libertariansim

As I’m working my way through Thomas Flint’s excellent book on Divine Providence, I enjoyed a short argument of his for libertarian free will which I think gives a nice formalization to an intuitive reason that many people have for being libertarians.  First, we will define some terms as Flint presents them and then present his argument(s).  Most of this post can be found on pages 22-19 of his book, which I highly recommend reading.

Basic Definitions

The first term that needs defining is free will.  There is much debate about what free will actually is and whether or not the principle of alternate possibilities is required for it, but Flint provides the simple definition that an action is free if doing otherwise is genuinely open to us.  Even though having the ability to do otherwise might not be necessary for an act to be free, it seems like this is a reasonable enough definition to cover many, if not most, actions that we would label as free.

The next two definitions needed are those of libertarianism and compatibilism.  Consider the following three propositions:

  1. Some human actions are free.
  2. All human actions are ultimately causally determined by events not under the causal control of their agents.
  3. It is not possible that a free human action be ultimately causally determined by events not under the causal control of it’s agent.

Libertarianism is then defined as the conjunction of (I) and (III) while compatibilism is the conjunction of (I) and (I).  Hard determinism is the conjunction of (II) and (III), but it is of little importance for this post.  Most people generally begin with the belief in libertarianism and then after reading up on the philosophy or theology of the issue either decide on libertarianism or compatibilism (in the case of Christians), or end up as determinists (in the case of atheistic naturalists).  Let us now turn to Flint’s succinct argument.

The Unavoidability Argument

I am calling this argument “the unavoidability argument” even though Flint gives it no does not name it because it captures the essence of what he argues.1  It is most accurately an argument against compatibilism, rather than an argument for libertarianism, but since Flint is presenting Christian views on free will, an argument against compatibilism is also an argument for libertarianism, since hard determinism is incompatible with certain Christian claims (such as man is morally responsible for his sin).

If causal determinism is true, then this means that my actions are not genuinely up to me, rather they are determined by the environment, my nature, or any number of things.  These things are not up to me, they are unavoidable facts about the world in which I live and about myself.  In the same way, the fact that they cause me to act in a certain way is also not up to me, it is another one of those unavoidable facts.  Therefore, the way in which I act is unavoidable for me, and hence I could not have genuinely done otherwise and am not free.

Letting U(E) stand for “event E is unavoidable for me” and  “E→A”  stand for “E implies I perform action A”, then we can formalize the argument as follows:

  1. U(E)
  2. U(E→A)
  3. Therefore, U(A)

Event E is the sum of all relevant facts about myself and the world, it is all of those true facts that cause me to make a certain decision and they are certainly not up to me whether or not they are true.  U(E→A) states that if E obtains, then so does A, and this is also not up to me, assuming (II) is true.  Then the conclusion follows relentlessly from the premises.  Since A is unavoidable, it cannot be genuinely free because I could not have genuinely done otherwise.

The only way that I can see to avoid the conclusion of this argument is to adopt a differing account of what makes an action free.  Certainly denying the principle of alternate possibilities seems to be a promising way to proceed, but then it is likely that a parallel argument can be run.

The traditional libertarian escapes this argument by denying (2).  Whether or not I perform A after events E is genuinely up to me.  The circumstances in which I find myself do not necessitate that I perform any given action, and so it is premise (2) on which the compatibilist and the libertarian disagree.

Another noteworthy use of this same argument is when we take U(E) to mean “I am morally responsible for E”.  The argument is still valid for this and, if causal determinism is true, then (1) and (2) certainly are true.  I am not morally responsible for events outside of my control and neither am I morally responsible for the conditional E→A since it is causally determined.  Hence, neither am I morally responsible for my performing action A.


On the basis of this simple argument, I believe that Christians have good reasons for being libertarians with respect to free will.  As Christians, our only viable options are libertarianism and compatibilism, and this family of arguments gives good reasons for preferring libertarianism over and above compatibilism.  For the non-Christian, hard determinism remains a viable option should he reject libertarianism.

1. After posting, it was brought to my attention that this argument is
merely a simpler version of van Inawagen’s Consequence Argument, see here.

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