One of the common themes in biology and medicine is the feeling that somehow there must be more. Creationist cults simply know that life must be more than matter, and mind-body dualists (which includes most alternative medicine advocates) are certain that humans are more than an "ugly bag of mostly water" (sorry for the geek reference). If you can stick with me here, I'll explain to you a bit of the history surrounding this fallacy.
Most of us intuitively feel that we are both a body and a person. In every day life, it makes a certain operational sense to think of our "mind" as being something distinct. From a biological standpoint, however, this doesn't work as well.
Biology was one of the last of the "natural philosophies" to become a science. It was clear to those who studied chemistry and physics that certain principles seemed to explain the natural world, but those who studied living things were mostly involved in description. Still, biology has become a science in its own right. According to Ernst Mayr, one of the greatest biologists of the last century, a number of events preceded biology being recognized as a legitimate science. One vital event was the recognition that all biological processes were constrained by the laws of physics and chemistry. Another important step was the rejection of two erroneous principles: vitalism, and teleology.
Teleology is the idea that there is some larger end-point or goal that drives biological processes, such as the idea of the ladder of ascent where the development of life has had, as its goal, the creation of more and more complex forms. Darwin's synthesis of natural selection and evolution pretty much destroyed this idea. Clearly, if stochastic processes can drive the changes we see in living beings, determinism is out the door. Evolution has elements that are random (changes in environment, mutations, etc.) but other elements that are decidedly non-random (for example, convergent adaptations are difficult to call "random"---sure the processes that underlie them are random, but these processes and pressures lead to a non-random result). But from a "cosmic" standpoint, there is no room left for teleologic explanations.
More offensive to me as a physician is the idea of vitalism. This ancient principle says that the difference between living and non-living things is some sort of non-material vital force. As the natural philosophers of the last few centuries became more sophisticated, they worked with this assumption and tried to define it scientifically. For example, it was felt that organic and inorganic matter differed in that, if melted with heat, only inorganic matter could re-crystalize naturally with the removal of the heat source (since we obviously cannot add that essential vital force). This seemed to give a "scientific" way of testing whether or not something was from a "living" source. If this were found to be true, it might pave the way for more experiments that could help show that there must be some sort of "elan vital" that animates living matter. In 1828, a chemist named Friedrich Wohler synthesized urea, an organic compound, from two inorganic compounds. In other words, he created "life" from "non-life".
This, and experiments like it, effectively destroyed the best attempt to use knowledge of natural laws to divide living from non-living systems. The implications were probably unimportant to Wohler and many others, but from a modern perspective, this is seen as the beginning of the end for vitalism.
The death of vitalism, and the discovery of genetics, allowed biology to grow into a mature scientific discipline. There are no processes in biology that have not been amenable to scientific investigation or that have required a deus ex machina to fully understand. That doesn't mean that vitalism is dead. Since we, as human beings, operationally see ourselves and both "mind" and "body", we will always be tempted to think vitalistically.
This is especially true in the most anthropocentric of sciences, medicine. All alternative medicine is based on the idea that we are more than biology, that there is some force, some elan vital that animates us and elevates us.
- Chiropractic uses the concept of "vertebral subluxation complexes" that block the flow of vital energy, despite the lack of any evidence for these things.
- Acupuncture, reiki, and other "energy therapies" claim to affect the role of qi, or vital energy, a non-organic, immeasurable force that animates us. Such a vital force has never been found.
- Homeopathy makes claims that some sort of magic happens to water when they shake it just right. In this case, it's actually the water that has some sort of vital force imposed upon it, but then this magic water is supposed to be able to affect human biology via a presumably equally invisible and immeasurable process.
If something is immeasurable and un-observable, either directly or indirectly, then it is not medically relevant. Remember, if you are claiming that an intervention is helping a patient, then you are claiming that it is measurable and observable.
If a measurable, observable phenomenon is better explained by known physical laws than by a vitalistic explanation, then why make up a silly, non-reality-based explanation?
Vitalism, an ancient and discredited philosophy, has become irrelevant in modern thinking with two important exceptions: alternative medicine, and religion. That, right there, should tell you something important.