The big problem with parapsychology as a field is that science is all of a piece. Thus, physics is consistent with chemistry, biology and so on. So the question is not “what knowledge can we derive on the assumption that we know nothing?”—but “what knowledge can we derive given what we know already?” And we know really quite a lot about areas that directly impinge on this question.
Basic physics leaves it not looking good for parapsychology as a field in any way. Sean M. Carroll points out that both human brains and the spoons they try to bend are made, like all normal matter, of quarks and electrons; everything else they do is properties of the behaviour of quarks and electrons. And normal matter, made of quarks and electrons, interacts through the four forces: strong, weak, electromagnetic and gravitational. Thus either it’s one of the four known forces or it’s a new force, and any new force with range over 1 millimetre must be at most a billionth the strength of gravity or it will have been captured in experiments already done. So either it’s electromagnetism, gravity or something weaker than gravity.
This leaves no force that could possibly account for telekinesis, for example. Telepathy would require a new force much weaker than gravity and a detector in the brain evolved to use it for signaling. Precognition, the receipt of information transmitted back in time, would violate quantum field theory.
What this means is that these ideas have pretty much no chance of being right even before we test them directly.
Treating parapsychology as having zero chance of working rather than “but there’s still a chance, right?” of working does have the philosophical problem that it would require dismissing out of hand any positive results, rather than properly evaluating them as merely ridiculously unlikely. However, this is unlikely to be a practical problem while well-designed tests show no positive results, and the only tests showing any positive results tend to exhibit the experimental design skills of Daryl J. Bem.
(The above is large chunks of the RationalWiki article, but I wrote those chunks too ;-) )
The big problem with parapsychology as a field is that science is all of a piece. Thus, physics is consistent with chemistry, biology and so on. So the question is not “what knowledge can we derive on the assumption that we know nothing?”—but “what knowledge can we derive given what we know already?” And we know really quite a lot about areas that directly impinge on this question.
Basic physics leaves it not looking good for parapsychology as a field in any way. Sean M. Carroll points out that both human brains and the spoons they try to bend are made, like all normal matter, of quarks and electrons; everything else they do is properties of the behaviour of quarks and electrons. And normal matter, made of quarks and electrons, interacts through the four forces: strong, weak, electromagnetic and gravitational. Thus either it’s one of the four known forces or it’s a new force, and any new force with range over 1 millimetre must be at most a billionth the strength of gravity or it will have been captured in experiments already done. So either it’s electromagnetism, gravity or something weaker than gravity.
This leaves no force that could possibly account for telekinesis, for example. Telepathy would require a new force much weaker than gravity and a detector in the brain evolved to use it for signaling. Precognition, the receipt of information transmitted back in time, would violate quantum field theory.
What this means is that these ideas have pretty much no chance of being right even before we test them directly.
Treating parapsychology as having zero chance of working rather than “but there’s still a chance, right?” of working does have the philosophical problem that it would require dismissing out of hand any positive results, rather than properly evaluating them as merely ridiculously unlikely. However, this is unlikely to be a practical problem while well-designed tests show no positive results, and the only tests showing any positive results tend to exhibit the experimental design skills of Daryl J. Bem.
(The above is large chunks of the RationalWiki article, but I wrote those chunks too ;-) )