reasoning
If the pandemic resulted from a lab-developed virus (accidental or deliberate), certain evidence could plausibly have emerged by now but has not: no whistleblower has given first-hand testimony or exposed a COVID-lab link (even though some doctors/researchers have spoken out about other Chinese mishandling of COVID information); there are no published records of SARS-CoV-2 in virus databases or research grants; and Wuhan was not immediately cordoned off when the first cases appeared. This missing evidence downweights the lab-linked hypotheses. Factors: lab-escape ÷2.4, bioweapon ÷1.2, zoonotic-collection ÷1.7. Final likelihoods: Zoonotic 3.2%, Lab-escape 89%, Bioweapon 4.5%, Zoonotic-collection 3.2%.
Step 6 verdict — approved (checked)
Reconstruction. Premises: (i) under a lab-linked origin, at least some of {whistleblower testimony, a pre-outbreak SARS-CoV-2 record in databases/grants, an immediate cordon of Wuhan} would plausibly be observable by now; (ii) none has been observed. Load-bearing step: absence of evidence that is expected-if-H lowers the posterior on H.
Evaluation. This is the valid Bayesian schema P(H | ¬E) < P(H) whenever P(E | H) > P(E | ¬H). Conditional on the premise that the listed evidence is genuinely more expected under lab-linked than under zoonotic origin, the downweighting follows for all three lab-linked variants (including zoonotic-collection, whose collected precursor would also leave a database/grant trail). The inference holds; it applies to H-42/H-43 with no observation attached, feeding step 7. Probes that look like defeaters — a censored regime suppressing whistleblowers, authorities not knowing to cordon, a bioweapon program not publishing — all attack whether P(E | H) is really high, i.e. premise (i)‘s magnitude, not the inferential move. Those are priced as the step-7/8 weight (the specific ÷2.4/÷1.2/÷1.7 factors are strength, not validity). Traced myself; author-blind.