Hence, we arrive at the post-modern concept of explanatory pluralism, which states that explanatory stories can exist at multiple levels, all of which correspond to the facts, but none of which can be derived from the other. The lack of ability to derive, for example, the spiritual explanation from the biochemical explanation does not make either story "wrong". Both are equally acceptable. We don't have to understand the linkage between levels of explanation. We can accept a good story on its own level without reference to any other level. This reminds me of a talk I gave at a Catholic hospital in which one of the physicians present asked me to explain the mechanism of action of prayer. Luckily, in that hospital, I could defer to the administrator, a Dominican nun. However, the appropriate answer is to challenge the question. It is not necessary to establish a mechanism of action for prayer to accept that prayer helps some people some of the time in some places. I don't need to know how it does that to accept this statement.
Both Popper and Abelson argued that scientific theory, and human knowledge generally, is generated by the creative imagination in order to solve problems that have arisen in specific historio-cultural settings. Abelson writes that knowledge does not exist independently of a purpose for which it can be used. Knowing Juliette's hair color helps me to recognize her. This is the point of a story to tell us how to do something to accomplish a purpose. Thus, our stories about health and disease are meant to help us to get well or help someone else get well.
In All Life is Problem Solving, Popper sought to explain the apparent progress of scientific knowledge--how it is that our understanding of the universe seems to improve over time. He wrote that, in response to a given problem situation, a number of competing conjectures, or stories, arise. Then we attempt to determine which of these stories helps us best to solve our problem. Explanatory pluralism teaches us that we can use more than one story at the same time. We don't have to settle on just one best story. Science proceeds as a process of error elimination, performing a similar function for science that natural selection performed for biological evolution. Theories that better survive the process of refutation are not more true, but rather, more "fit"--in other words, more applicable to the problem situation at hand. We could argue that the current dialogue of conventional medicine with shamanism and other traditional cultural forms of healing arises out of the recognition (error elimination) that the pure biomedical model doesn't quite work. As we work toward the problem of greater healing, we need each other more and more.
Thus, how would we practice if we accepted explanatory pluralism. First, as Popper argued in his political philosophy, we would be intolerant of the intolerant. He wrote, "We should therefore claim, in the name of tolerance, the right not to tolerate the intolerant. We should claim that any movement preaching intolerance places itself outside the law, and we should consider incitement to intolerance and persecution as criminal, in the same way as we should consider incitement to murder, or to kidnapping, or to the revival of the slave trade, as criminal." (See The Open Society and Its Enemies: The Spell of Plato, by Karl Raimund Popper, Princeton University Press, 1971, ISBN 0-691-01968-1, pg 265).
Likewise, we must demand that conventional biomedicine cease its intolerance of other forms of healing. Medicine must recognize that it is just a story, also, and one that doesn't always work for everyone, everytime, in every circumstance. We're all in the same boat and we have to communicate or we'll get nowhere, tending to capsize. Without communication, none of us will survive. Collaboration must be the watchword and not intolerance or arrogance. Together we can explore the conditions under which our various stories work well or don't work, recognizing that this might be an unanswerable question related to larger forces that we can't even measure or comprehend yet. Nevertheless, we can be scientifically rigorous in our pursuit of the conditions under which some stories work better than others. As I suggested in Narrative Medicine, this invites us into a dialogue in which all healers (including physicians) have equal status with all stakeholders, including patients, their friends, and family members. When each storyholder presents his or her perspective to each shareholder, then the shareholders are free to debate and decide what combinations of stories they will use. Then, a true democracy arises in health care in which all stories can compete for the status of being chosen to be used in a clinical setting. I suspect this will do more than anything to move forward the evolution of medicine.
How do we make sense of how to make sense about this world of healing? I believe that scientific knowledge is constructed by scientists and not discovered from the world. I agree with the constructivists, who claim that the concepts of science are mental constructs proposed in order to explain our sensory experience. It thus is opposed to positivism, which is a philosophy that holds that the only authentic knowledge is that which is based on actual sense experience.