A critique of Tversky and Kahneman's distinction between fallacy and misunderstanding

Tversky and Kahneman explain cognitive errors in terms of either misunderstanding or fallacy , but have failed to define these concepts. Therefore, they are unable to derive strict diagnostic criteria for distinguishing between them. The lack of conceptual clarification also has prevented them from recognizing the circular relationship between understanding and logicality. Diagnosis of understanding presupposes logicality, and diagnosis of logicality presupposes understanding. This circularity follows when understanding is defined as grasping what is and is not logically implied by a given expression as intended, and when fallacy is defined as logical error. Alternative definitions are discussed and rejected. Tversky and Kahneman fail to realize that one cannot explain and understand what is genuinely illogical, and that, therefore, errors must always be regarded as failure to understand, that is, as logical inference from erroneous premises.