We consider the proof search ("automatizability") problem for propositional proof systems in the context of knowledge discovery (or data mining and analytics). Discovered knowledge necessarily features a weaker semantics than usually employed in mathematical logic, and in this work we find that these weaker semantics may result in a proof search problem that seems easier than the classical problem, but that is nevertheless nontrivial. Specifically, if we consider a knowledge discovery task corresponding to the unsupervised learning of parities over the uniform distribution from partial information, then we find the following:• Proofs in the system polynomial calculus with resolution (PCR) can be detected in quasipolynomial time, in contrast to the n O( √ n) -time best known algorithm for classical proof search for PCR.• By contrast, a quasipolynomial time algorithm that distinguishes whether a formula of PCR is satisfied a 1 − fraction of the time or merely an -fraction of the time (for polynomially small ) would give a randomized quasipolynomial time algorithm for NP, so the use of the promise of a small PCR proof is essential in the above result. • Likewise, if integer factoring requires subexponential time, we find that bounded-depth Frege proofs cannot be detected in quasipolynomial time. The final result essentially shows that negative results based on the hardness of interpolation [31,13,11] persist under this new semantics, while the first result suggests, in light of negative results for PCR [22] and resolution [2] under the classical semantics, that there are intriguing new possibilities for proof search in the context of knowledge discovery and data analysis. * Combines and largely subsumes two earlier technical reports, [26] and [25] †