From year to year medicine becomes more and more complex and splits into many sub-specialties which focus on diseases while tending to ignore the patient himself. Amidst this schism epidemiology thrives. Surrounded by an aura of genuine science it seems to provide the desired unifying principle for medicine. Yet a closer look at its basic premises reveals the opposite. At best it can state that lung cancer is associated or correlated with smoking.
Epidemiology is incapable of distinguishing between the three.
The conclusion is in the hands of medicine. Instead of considering the relationship between smoking and cancer in its entire complexity, epidemiology focuses on a small number of variables, dismissing the rest as negligible, which is unfortunate since for the individual patient nothing is negligible. The same approach underlies many epidemiological studies, particularly clinical trials, that involve simplifications and presumptions which breed false conclusions and should be regarded by the medical community with suspicion. As long as epidemiological statements do not contradict medical experience the harm to the patient may be small since they can always be corroborated by clinical observation. Yet epidemiology threatens to impose its deceptive reasoning on medical issues that are far less obvious, e.g., cancer treatment which today is directed by clinical trials.