Topic description:
Disease is so familiar that even those concerned with it professionally fail to recognize its conceptual complexity. Many of our perceptions about disease have been adopted uncritically from medicine's long and at times, unscientific, tradition. In recent years, evolutionary ideas – which form the bedrock of modern biological thinking – have come to be applied to disease. However, it has been medical notions of disease to which these ideas have really been applied rather than biological ones. This is potentially problematic; a more accurate biological understanding of this and other medicinal terms is, therefore, necessary. Focusing on the terms 'illness', 'pathology' and 'disease' and their interrelationships, this paper presents a synopsis of some of the ideas explored while I was a Visiting Fellow at the KLI during the summer of 2005. It is suggested that 'illness' has greater biological significance than is usually realised, especially in terms of individual survival; that the term 'pathology' needs to be distinguished from ‘disease’, and care be taken to use this term to refer to specific organic characteristics, and that 'disease' be better understood as a label that represents sets of experientially subjective and physiologically objective phenomena that contribute to alterations in the overall biological state of an individual as an organism. Health is mentioned briefly and also envisaged as being a biological state only configured differently to that associated with disease. Some of the consequences of these findings are considered in relation to Darwinian medicine and how they might affect research strategies. Significantly, it is suggested that disease should not be considered in a simplistic, unitary way but as a set of organic responses. Each of these responses should be understood in their own right, in relation to others and in terms of their effect, individually and in combination, on the individual as an organism. 

Biographical note:
After working as a radiographer, Stephen Lewis took his first degree in Human Biology at Surrey University and then, after further radiographic practice, a PhD (Studies in Catch Up Growth in the Rat Skeleton) at University College, Cardiff. While working as a prosector and demonstrator in the Anatomy Department at Cardiff he took an MA degree in the History of Philosophy. He then moved to Chester College as a senior lecturer in the Department of Health and Community Studies, later transferring to the Department of Biological Sciences where he now lectures in Evolutionary Biology and other subjects in the Health Sciences programme. Dr. Lewis also serves on the Committee of the Society for the Study of Human Biology. Following his early interests in morphology (particularly variation in anatomical phenotype, skeletal growth, and morphology) in which he maintains an interest, Dr. Lewis is now primarily interested in the biological and philosophical understanding of health and disease. This change of direction coincided with the emergence of the field of 'Darwinian Medicine' with which he has been associated via his personal website where some of his ideas are more readily available. Dr. Lewis was a Visiting Fellow at the KLI during the summer of 2005.