To the original concept are appended the epistemic notion of uncertainty and the moral notion of malaise, among other things. Now it could be maintained that if there is contingency of events, then there must be uncertainty and unpredictability about what happens. And it could equally be maintained that where there is uncertainty, there will inevitably be a certain intellectual disquiet. Thus both uncertainty and malaise could reasonably be associated with contingency. Rorty is a great believer in the potency of a vocabulary, and I think that incorporating the three under the single designation of contingency puts a spin on the situation which rather distorts Santayana's position.
Matters remain much clearer with the old traditional usage.
Santayana has quite different reasons in each case for holding the three beliefs. He attributes his strong conviction that all events in the material world are contingent to the doctrine of essence, for essences invariably open up alternative possible paths for events to follow at each stage. He also appeals to a trumping argument that any pattern we might find among events itself may rest at a deeper level upon contingency. His scepticism about literal knowledge of facts has an entirely different ground, being founded upon his naturalist picture of animal life immersed in the cosmos. Creatures have no contact to their surroundings save through special sensory organs which generate in the mind essences that are original and dependent on the nature of mind no less than on the external reality.