I think, Chomsky's point is that certainty and negativity are two related concepts presupposing each other, forming the very basis of conceptuality as we know i

I think, Chomsky's point is that certainty and negativity are two related concepts presupposing each other, forming the very basis of conceptuality as we know it (or, maybe better: how it is relevant for us). Stochastic probability is neither of this, nor does it promise to lead towards this.