In all traditional societies, stories are told of men and women with seemingly miraculous powers, and such powers are acknowledged by all religions. In many parts of the world, various psychic abilities are cultivated within systems such as shamanism, sorcery, tantric yoga, and spiritualism.
And even within modern Western society, there are persistent reports of unexplained phenomena, such as telepathy, clairvoyance, precognition, memories of past lives, hauntings, poltergeists, psychokinesis, and so on. Surveys show that the most common kind of telepathy occurs in connection with technology, namely telephone telepathy, whereby people think of someone for no apparent reason who calls soon afterward.
Although dogmatic skeptics dismiss all this evidence out of hand, the possibility that at least some of these events actually occur is an open question. It can be answered only after an examination of the evidence.
The scientific study of allegedly psychic phenomena has now been going on for more than a century. Investigators in this field of psychic research have discovered some cases of fraud, and found that some apparently paranormal events can in fact be explained by normal causes. But there remains a large body of evidence that seems to defy explanation in terms of any known physical principles.
Numerous experiments designed to test for so-called extrasensory perception have yielded positive results with odds against chance coincidence of thousands, millions, or even billions to one.
Insofar as these phenomena cannot be explained in terms of the known laws of physics and chemistry, from the mechanistic point of view they ought not to occur. But if they do, then there are two possible approaches. The first is to suppose that they depend on nonphysical causal factors or connecting principles. The second is to start from the assumption that they depend on laws of physics as yet unknown, or on extensions of quantum theory, for example by postulating that mental states play a role in determining the outcomes of probabilistic processes of physical change.
This brief consideration of the outstanding problems of biology does not offer much hope that they can all be solved by an exclusively mechanistic approach. In the case of morphogenesis and animal behavior, the question is open. The problems of evolution and the origin of life are insoluble per se and cannot help to decide between the mechanistic and other possible theories of life. The mechanistic theory runs into serious philosophical difficulties in connection with the problem of the limits of physical explanation; in relation to psychology, it leads to seemingly insoluble problems; and it is in conflict with the apparent evidence for parapsychological phenomena.
The prospects for improved versions of mechanistic, vitalist, and organismic theories are discussed in the following chapter. Morphogenesis is the starting point.