Incoherentism is the theory that at the bottom of all concepts there is a failure of sense. Incoherentism is the reflection of the failure of the words mean objects paradigm. Incoherentism is inherent in any attempt to render what is sometimes called ineffable sensible.
Incoherentism does not say that you should not say anything, rather it says what you say will be in some way incoherent. It also says that this problem is not to be corrected by any superior analysis.
Incoherentism is easily visible in opposing schools ability to disagree based upon some incoherence in the opposing theory.
Incoherentism thus does not mean an idea should be abandoned. Often it is thought that ideas that have an appearance of ‘real’ information can be discarded once the internal incoherence is exposed. This is not true. The idea persists, powered by the appearance, at least where the appearance has the character of ambiguity.
Of course we could say incoherentism presupposes a coherentism. But this coherentism is the φantasy of the ‘words mean objects’ paradigm. In this sense incoherentism is just an expression for the nature of language.