Free Will A Contemporary Introduction

The Debate over the Consequence Argument 87

proposition involving metaphysical necessity. That is, the Consequence Argu-
ment does not proceed under the supposition that the facts of the past or the laws
of nature are metaphysically necessary truths. And this is as it should be, since—
barring further special metaphysical assumptions not needed for specifying the
thesis of determinism—they are best thought of as contingent and not necessary
truths.^17 Hence, the argument proceeds under the assumption that, although these
truths, Po and L in particular, are merely contingent and not necessary, they are
nevertheless power necessary for a person, or, as van Inwagen would put it, they
are such that no one has, or ever had, any choice about them.
Consider now van Inwagen’s formulation of the entire argument. In doing so,
note again that we are treating P to be the proposition that Richard Nixon was
pardoned for any crimes he committed while he was President of the United
States, and recall that it was his successor as President, Gerald Ford, who par-
doned him.

1. □((Po&L) → P) assume determinism is true and that P


2. □(Po → (L → P)) apply logic to step 1


3. N(Po → (L → P)) apply Rule α to step 2


4. NPo introduce premise, Principle of Fixity of Past


5. N(L → P) apply Rule β to steps 3 and 4


6. NL introduce premise, Principle of Fixity of the Laws


7. Therefore, NP apply Rule β to steps 5 and 6

If the above modal formulation of the Consequence Argument is sound, and if
determinism is true, no one, including Gerald Ford, had any choice about
whether Nixon was pardoned for his crimes in office. And for any action per-
formed by any person, the same applies. In short, if this argument is sound, then
if determinism is true, no one is able to do otherwise, and, hence, no one has
leeway freedom.
With one minor exception, our preceding discussion should have made every
step in the above argument transparent. That exception is the step from 1 to 2.
The reason the step is a valid one is because it follows from basic logic. Steps 1
and 2 are logically equivalent, and logically equivalent substitutions in an argu-
ment are permissible.^18 But what is important to understand is why the substitu-
tion from the formulation of 1 to the formulation to 2 is made prior to applying
Rule α. The reason is that it permits the introduction of NPo at step 4 as a sepa-
rate premise, as well as the introduction of NL at step 6 as a separate premise,
rather than as a single premise of the form N(Po&L). Otherwise, if Rule α were
to have been applied to step 1 (rather than step 2), the argument would instead
most naturally have to be set out as follows:

1. □((Po&L) → P) assume determinism is true and that P


2. N((Po&L) → P) apply Rule α to step 1


3. N(Po&L) introduce premises, Principle of Fixity of Past and Laws


4. Therefore, NP apply Rule β to steps 2 and 3