In 1987 Marcello Truzzi revived the term specifically for arguments which use scientific-sounding language to disparage or refute given beliefs, theories, or claims, but which in fact fail to follow the precepts of conventional scientific skepticism. He argued that scientific skepticism is agnostic to new ideas, making no claims about them but waiting for them to satisfy a burden of proof before granting them validity. Pseudoskepticism, by contrast, involves “negative hypotheses” - theoretical assertions that some belief, theory, or claim is factually wrong - without satisfying the burden of proof that such negative theoretical assertions would require.

In 1987, while working as a professor of sociology at Eastern Michigan University, Truzzi gave the following description of pseudoskeptics in the journal Zetetic Scholar (which he founded):

In science, the burden of proof falls upon the claimant; and the more extraordinary a claim, the heavier is the burden of proof demanded. The true skeptic takes an agnostic position, one that says the claim is not proved rather than disproved. He asserts that the claimant has not borne the burden of proof and that science must continue to build its cognitive map of reality without incorporating the extraordinary claim as a new “fact.” Since the true skeptic does not assert a claim, he has no burden to prove anything. He just goes on using the established theories of “conventional science” as usual. But if a critic asserts that there is evidence for disproof, that he has a negative hypothesis—saying, for instance, that a seeming psi result was actually due to an artifact — he is making a claim and therefore also has to bear a burden of proof.

— Marcello Truzzi, “On Pseudo-Skepticism“, Zetetic Scholar, 12/13, pp3-4, 1987

Truzzi attributed the following characteristics to pseudoskeptics:

  1. Denying, when only doubt has been established
  2. Double standards in the application of criticism
  3. The tendency to discredit rather than investigate
  4. Presenting insufficient evidence or proof
  5. Assuming criticism requires no burden of proof
  6. Making unsubstantiated counter-claims
  7. Counter-claims based on plausibility rather than empirical evidence
  8. Suggesting that unconvincing evidence provides grounds for completely dismissing a claim

Truzzi characterized “true” skepticism as:

  1. Acceptance of doubt when neither assertion nor denial has been established
  2. No burden of proof to take an agnostic position
  3. Agreement that the corpus of established knowledge must be based on what is proved, but recognising its incompleteness
  4. Even-handedness in requirement for proofs, whatever their implication
  5. Accepting that a failure of a proof in itself proves nothing
  6. Continuing examination of the results of experiments even when flaws are found

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