威廉姆森（Timothy Williamson）在《哲學的哲學》（The Philosophy of Philosophy）中就如何理解反事實條件句提出了一種反事實認識論，在這種理論的基礎上提出了一種經典邏輯樣式的模態理論，即經典模態邏輯T。基於對威廉姆森理論的扼要闡釋，從反事實認識論的直覺主義視角可以得出模態邏輯T的直覺主義版本；同時也可以參照威廉姆森為經典邏輯所做的溯因辯護，對直覺主義邏輯提供一種威廉姆森式的溯因辯護，從而回應威廉姆森針對直覺主義邏輯提出的反對意見。

In The Philosophy of Philosophy, Timothy Williamson argues for how to understand counterfactual conditionals, epistemology of counterfactuals, and on the basis of which a modal theory in the style of classical logic is given, that is classical modal logic T. Based on a brief rehearse of Williamson’s theory, a corresponding intuitionistic version of T can be derived from the perspective of the epistemology of counterfactuals. In the meantime, an abductive defense in a Williamson-style for intuitionistic logic can be given by analogy with the same kind of defense for classical logic, so that Williamson’s objection to intuitionistic logic can be responded.