The recently published book Debating Psychic Experience, edited by Stanley Krippner and Harris L. Friedman, includes some brief but fascinating speculation by parapsychologist Dean Radin about a possible connection between psi and quantum mechanics. Though such claims are often lambasted by critics as mere New Age handwaving, Radin points out that there is a growing body of empirical evidence suggesting that quantum effects are not limited to the smallest scale of existence.
The open question [is] whether quantum effects operate in the brain. This is an active debate, with some arguing in the affirmative (Josephson & Pallikari-Viras, 1991; Stapp, 1999), and others in the negative (Smith, 2009). While the debate continues to unfold, it is worth considering that quantum interconnections easily observed at the microscopic scale do not magically vanish in macroscopic systems. They just become more complex. Our present ability to detect connections in macroscopic systems is rapidly advancing, and there is already evidence that quantum effects are found not only in exotic conditions, but in everyday macroscopic systems.
For example, according to Vedral (2008), "Traditionally, entanglement was considered to be a quirk of microscopic objects that defied a common-sense explanation. Now, however, entanglement is recognized to be ubiquitous and robust" (p. 1005). Physicists have observed high quality quantum correlations in diamond that persist on millisecond time scales at room temperature (Neumann et al., 2008), in macroscopic mechanical membranes (Thompson et al., 2008), in photosynthesis (Engel et al., 2007), in electronic circuits (Ansmann et al., 2009) and in avian magnetonavigation (Solov'yov & Schulten, 2009). These developments, all occurring since the turn of the twenty-first century, suggest that quantum processing in the human nervous system is no longer unthinkable. Indeed, given the pace of progress today in quantum biology, it seems inevitable. What is the consequence of this "new" reality for understanding psi?
It means that we need to reframe our understanding of physical objects and what they may be capable of, including the brain. The quantum brain would no longer be exclusively locked inside the skull; parts of it would reside beyond the classical boundaries of space and time. This means that brain processes responsible for ordinary perception, and all the other cognitive processes studied by the neurosciences, may be influenced not only by local sensory information, but by impressions received from what common sense would label "at a distance."
With the brain viewed as a quantum object, people who are asked to keep each other "in mind" would be entangled not just emotionally, but physically. Those brains might "co-process" information regarded as important by both individuals, and as such these psychophysical entanglements might explain the remarkable coincidences reported between separated loved ones and identical twins. For example, Playfair (2003) reports a case (one of many) in which a healthy man suddenly experienced a suffocating pain in his chest while hundreds of miles away, at the same moment, his identical twin was suffering a heart attack.
[Debating Psychic Experience, pp.124-125]