Medical diagnosis is a difficult task that combines intellectual and intuitive skills. Well-defined diseases with structural changes in tissues are the easiest diagnose. Because we rely a lot on pictures, mass lesions such as tumors and tissue distortions from infection and injury are the easiest to visualize and diagnose. However, most common health problems that physicians see every day cannot be visualized and remain in a curious limbo. More and more people are entering this limbo every day and there is increasing disenchantment with a medical system that has a hard time recognizing illnesses that you cannot see or measure by simple tests.

Medical knowledge is imperfect at best, clinical practices vary, outcomes are seldom measured, physicians are refractory to change and patients have ideas of their own which do not coincide with either existing practices, nor academic guidelines. Some patients conclude that the existing medical system is so far off the mark that they walk away vowing never to go back unless they are in a car accident and have no choice. Many Doctors are discouraged and face an increasingly difficult if not impossible task of  following numerous guidelines, and trying to satisfy too many stakeholders, often with conflicting interests - patients, insurers, employers, government agencies, drug companies, professional peers and overseers.

Doctors are understandably interested in objective evidence and want test results to confirm their diagnoses. However, most  pathophysiological processes remain obscure and are genuinely difficult to measure, characterize and understand. Most medical technology addresses the needs of a few well-defined diseases. The specification of coronary artery disease, for example, can be precise and is a tribute to the combined effort of physicians, technicians, engineers and equipment manufacturers to fully reveal a pathophysiological process. The precision of these well-defined areas of medical concern may mislead the unwary into thinking that all areas of medicine are equally well-defined or can be well-defined with just a little more effort.

Common syndromes are diagnosed on clinical grounds often with no objective evidence whatsoever. While the history of migraine headaches is distinctive and an astute clinician will have no difficulty making the diagnosis on history, the emergency room physician will have trouble deciding if a patient with a migraine story is really suffering or simply wants a narcotic drug. The diagnosis of depression is another subjective syndrome that requires a historical understanding more than X-Rays or abnormal lab tests. The irritable bowel syndrome is a diagnosis of exclusion. The patient may suffer a great deal but tests are negative repeatedly.

Medical practice is now under scrutiny from many directions. The idea of practice guidelines and problem-solving algorithms have been around for many years, but now are the subject of heated debate. Many scholars have realized that research findings do not get incorporated into medical practice - indeed with the proliferation of information, there is less formal direction in the selection and application of knowledge. Most astute observers will notice that medical practice goes with fads and fashions. The most important problems such as the effect of food and the environment on human health are usually ignored in medical practice.

Pragmatic, primary medicine is especially difficult because of the wide-range of disorders that present in all stages of manifestation. The primary physician must deal with patients with common syndromes, lacking objective specification, with early illness that may eventually become well defined, with in-between illnesses mingled with injuries, infections, addictions and psychosocial problems. Patients are often demanding and often have unrealistic expectations. There are ample reasons for physicians and patients alike to become dissatisfied with their traditional relationship and as the 20th century closed, a critical re-evaluation is medicine was taking place. Old assumptions are often revealed to be inadequate or wrong, with a few exceptions, the value of drug therapy is often limited and the results of clinical trials are often contradictory or confusing.     

A shift from category diagnosis to understanding the process underlying diseases is helpful to understand the patient, but is often not acceptable to agencies who pay the medical bills. The insistence on a disease category works against understanding disease; everyone wants to know what this is called and not where it came from and how to prevent it from happening. A patient with 80% coronary artery blockage gets the best treatment in our system; a single mother with a food-related illness may be living on welfare because she is too sick to work, but she gets little understanding and no technology is applied to solving her health problem. She remains on welfare and because  two of her three children develop a similar chronic illness, the family's future is bleak.

Despite the most impressive growth in biological knowledge and biotechnology, health care costs continue to grow, death  from cancers continues unchanged, bacteria continue to develop antibiotic resistance, HIV continues to spread, environmental degradation continues, alcohol and drug abuse remain major societal problems, violence increases, the climate changes erratically with costly devastation from floods, fires, winds and drought.