Instability, Modus Ponens and Uncertainty of Deduction

Considering the instability of nonlinear dynamics, the deductive inference rule Modus ponens itself is not enough to guarantee the validness of reasoning sequence in the real physical world, and from similar cause cannot gain similar result. Some kind of stability hypothesis should be added in order to draw meaningful conclusion. So the uncertainty of deductive inference appears the same as that of inductive inference, and the asymmetry between deduction and induction becomes unrecognizable in a way just like the case that the fundamental cleavage between the truth which are analytic and truth which are synthetic is ill-founded as W.V.O.Quine pointed out. Induction is not worse than deduction from a pragmatic stand.