Impermissible Hindsight in the MPEP

Answer in brief

Impermissible hindsight is using the applicant's own disclosure as a roadmap to combine prior art. MPEP 2142 says it "must be avoided and the legal conclusion must be reached on the basis of the facts gleaned from the prior art". Any reconstruction is proper only if it relies on knowledge within ordinary skill at the time.

Where the MPEP addresses it

MPEP 2142: the prima facie case and avoiding hindsight.
MPEP 2145(X)(A): when a hindsight argument succeeds.

Making the argument

Show the rejection cites no reason in the prior art or ordinary knowledge for the combination, beyond what the application itself teaches.

Sources for this entry

USPTO — MPEP § 2142 USPTO
Official text of this section, Ninth Edition, Revision 01.2024.
USPTO — MPEP § 2145 USPTO
Official text of this section, Ninth Edition, Revision 01.2024.
Wysebridge MPEP Center Wysebridge (publisher of this site)
The full MPEP (9th Ed., Rev. 01.2024) free to read, with Wysebridge's estimated patent bar weight for each chapter.

Practical guidance is original editorial content. Company-published figures are the company's own claims and are labeled as such.

Continue this reading path

MPEP 2142: Prima Facie Obviousness MPEP 2145: Rebutting an Obviousness Rejection Teaching Away in the MPEP

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Cite or share this entry

MPEP.net. “Impermissible Hindsight in the MPEP.” Wysebridge Reference. Content reviewed 9 November 2026.
https://mpep.net/hindsight/