This came to mind after reading one of Steven Novella's blogs. In it he parrots skeptical mantras that are known to be wrong. I won't bother to address them here because they are addressed in detail in Entangled Minds. But I will respond to two comments. First:
"There is no proposed mechanism for ESP that amounts to a reductionist model based upon established physics or biology."
This is a peculiar complaint, because if we can only accept things in terms of what we already understand, then science is no longer an open system. It collapses into the worst sort of mindless dogma, and no genuinely new discoveries are possible. If you have any inclination to agree with Novella's comment, please read the history of science.
The second comment was:
"The lack of a possible or even hypothetical mechanism for ESP also means that ESP research is limited to anomaly hunting. All studies that propose to look for ESP (for example the research of Dean Radin or Rupert Sheldrake) are not looking for ESP (because no one knows what ESP is) but rather are looking for anomalies. In fact some researchers more honestly label what they are looking for as “anomalous cognition.”
I sometimes use the term anomalous cognition as a euphemism, mainly when I want to avoid freaking out academics. But psi research is absolutely not a "hunt for anomalies." Psi experiments are conducted to test, under rigorously controlled conditions, whether the experiences labeled telepathy, clairvoyance, etc., are what they appear to be (i.e. genuine ESP), or whether they are better understood as coincidence, delusion, or one or more cognitive biases. The anomaly label is valid only in the sense that verifiable effects are unexpected with respect to existing theories. But as I've mentioned above, to assume that nothing exists outside of what we already understand, especially when the effect is empirically and repeatable demonstrable (as some psi effects are), is exceedingly bad science.