Clinical evaluation: constructing a new model for post-normal medicine.

The current paradigm in medicine is served by an explanatory model based on scientific positivism. We argue that there are inherent weaknesses in this model: its basis on reductionism, its reliance on linear thinking and its failure to incorporate human values invite a revision of our thinking about knowledge in medicine. We propose that a fresh explanatory model should be based on complexity theory, and argue that this better suits the new era of post-normal medicine, where analytical and predictive power are obtained by stepping back and looking at the relationships and overall context of a system rather than forcing reality into a preferred disciplinary framework. Better at times to be vaguely right, we argue, rather than precisely wrong.