excluded middle
The law of excluded middle states that for every proposition, either this proposition or its negation is true.
In general, intuitionists allow the use of the law of excluded middle when it is confined to discourse over finite collections (sets), but not when it is used in discourse over infinite sets (e.g. the natural numbers).
In T&W Ross explains in great detail with many examples why reality cannot be bificurcated into the abstractly possible and impossible, nor, as a corollary, can it be described by propositions of judgments that neatly divide into the true and false.
When something can be considered possible (or true), there is usually no complementary negative space of what is impossible (or false).
Excerpts from Ross’s work to be added later.