Generally, diseases are physiological abnormalities, determined on the basis of a change in form, function or feeling, or on the basis of a physiological measure falling outside of some pre-determined range of values (normal range).

Three main classes or dimensions of cause are popularly grouped under the following headings:

Genetic: all and any heritable factors associated with a disease Environment: all and any non-heritable factors, particularly those related to physical and/or internal physiological environment.

Lifestyle: the exposure history of a person or activities, habits, and locations that constitute their sequence of lived environments and acts. This is dependent upon a person’s location, acts, and interactions.

These three groups constitute the majority of popular “explanations” for why disease occurs where and when it does. This disease is due to “faulty genes”, that disease is due to “environmental influences”, another disease is due to “lifestyle factors”, and so on. However, “explanations are not causes, but everywhere they are treated as if they were”. (quote, source unknown).

However, there are some clearer and more specific criteria for determining if a agent is causally connected to an effect we label a disease.