How Healthcare got here

In "Without Miracles" Gary Czicko describes three sets of beliefs as to how biological features, whether structural or behavioural fit their respective functions and specifically how that fit came about . Two of the three turned out to be wrong.
Fit by Providence is essentially the creationists posture. Things are believed to be as they are because some all powerful source decreed it so.
Fit by instruction is the mechanism whereby use and disuse in one generation transmit or "instruct" their effects to the next - the mechanism proposed by Lamarck. The specifics of beliefs about the operation of this mechanism are predicated on a common sense view of how use and disuse wil laffect subsequent generations.
Fit by selection is the Darwinian mechanism driven by random variation, transmission and differential survival.

It takes only little flexing to see these three mechanisms as the three phases of decision making in many different disciplines though focusing here on the care of the sick.

In medicine originally treatments would have been determined by appeal to supernatural authorities, in reality pronouncements of the therapist's teachers and this tradition persisted for many a century and indeed is still present. How to deal with a situation is well described in dogmatic terms which the therapist meekly follows. Much of (the appeal of) alternative medicine is predicated on this.

Medicine as it learned something reproducible about the human body (and mind) added to the traditional view the use of common sense or rationale. This or that approach was proffered on the basis that logically, in the light of current apparently relevant knowledge, it ought to be the best approach. As science developed this use of common sense became less "common" yet in the end decisions were still based on what ought to be true rather than anything we even remotely knew to be true. Some of course were true despite a lack of convincing demonstration or confirmation. This is analogous to Lamark’s inheritance of acquired characteristics for in any analysis is the perception as what is or is not to be usefully inherited is based on common sense, the fundamental mechanism at work here and in decisions based on rationale, an elaborately informed variant. These common sense interventions were and are transmitted by teaching and training to this day. One should of course emphasise that such common sense choices were informed by an exponentially growing body of biomedical scientific observations. This however still left most recommendations short of actual evidence of likely benefit over alternative approaches.

Medicine, a core element of Healthcare is now making the jump to a situation where its recommendations are selected from a body of tangible experience, recorded and counted in similar situations. Still not perfect but the current best we have. This is the Darwinian mechanism- assorted treatments are proposed, they are tried in controlled circumstances, the best are used and transmitted to the next generation of practitioners and the rest are discarded and largely forgotten - they, the majority of proposals become extinct. The collection of well selected approaches to assorted clinical situations is growing but still far fom comprehensive leaving many patients to be advised on the basis of rationale or dogma. The popularity of alternative medicine indicates that for many patients with selected afflictions this approach is entirely acceptable.