Two Principles:
PUC: Every event has a cause.
FWT: Sometimes people act freely.
A Principle about Incompatibility:
P and Q are incompatible if there is a valid argument from
P and some necessary truths to the denial of Q.
An Argument for Incompatibility
1. Every event has a cause. (PUC)
2. If every event has a cause, then everything we do is completely determined
by antecedent conditions.
3. If everything we do is completely determined by antecedent conditions, then
nobody ever acts freely.
4. Therefore, nobody ever acts freely. (denial of FWT) [1,2,3 MMP]
Another (Very Similar) Argument for Incompatibility
1. Sometimes people do things freely. (FWT)
2. If sometimes people do things freely, then not everything we do is completely
determined by antecedent conditions.
3. If not everything we do is completely determined by antecedent conditions,
then some events are not caused.
4. Therefore, some events are not caused. (Denial of PUC) [1,2,3 MMP]