Enthymemes keep at least one of the premises or conclusion unsaid. The assertions left unsaid are intended to be so obvious as to not need stating.
The reasonable man adapts himself to the world.
The unreasonable one persists in trying to adapt the world to himself.
Therefore all progress depends on the unreasonable man.
Here there is an unstated premise that progress comes about when a man tries to adapt the world to himself. While all the premises are true, it is arguable that a man is "unreasonable" because he is trying to change the world.