Source: DeGruyter.com, 2015
on the more cognitive system and problem-solving oriented side, progress has been slower and many questions concerning the cognitive nature and computational modelling of creativity, for instance in concept invention, idea generation, or inventive problem-solving, remain unanswered.
This delay in development is partially due to one of the fundamental questions in creativity research and computational creativity, namely the question for a general definition of creativity as cognitive capacity. While it usually seems straightforward for humans to recognise (or at least judge) the presence or absence of creativity in different forms of artistic performance or in a solution to a problem or task, giving an explicit characterisation of creativity or reasonably general criteria for deciding when an artefact, behaviour, or idea has to be acknowledged as creative has hitherto not been achieved.
… the lack of process models or mechanistically-informative theories which could serve as basis for a computational (re-)implementation of creativity.