Flexibility, Free Will, Determinism

Swerve can be conceived as a variety of flex, and rigidity is equivalent to inflexibility.  So Lucretius' contrast of Clinamen and rectilinear motion can be conceived as a difference of degree, not of kind.  Likewise, Peirce's criterion of Probability implies that his distinction between Tyche and Determinacy is one of degree, not kind.  Now, if flexibility can be attributed to natural causality, it is applicable to human volition, as well.  Accordingly, the Voluntary-Involuntary distinction is, as Aristotle originally conceives it, before getting exaggerated to Eschatological proportions by Theological commitments, nuanced.  In other words, human behavior is more or less determined, or, equivalently, more or less free, or, equivalently, more or less flexible.  The persistence of the Philosophical reduction of it to mutually exclusive absolutes reflects a continued Theological influence more than empirical evidence.