The Master Argument (Kyrieuon Logos) of Diodorus Cronus
This is perhaps the most philosophically important case. Diodorus constructed an argument that only the actual is possible — i.e., if something did not happen, it was never truly possible. This had direct bearing on Epicurean physics because it threatened atomic swerve (the parenklisis/clinamen): if determinism rules and only what occurs is possible, the swerve has no logical space to exist. Epicurus needed possibility to be real and open to preserve both the swerve and human free will. His counter was not to refute Diodorus's formal logic term by term, but to insist that the Canon and the evidence of human deliberative experience directly attest to real open possibility — and that no formal argument can override what is self-evident to experience.
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