Simon argued twice (1993, 1995) that connectionist neural networks qualify as physical symbol systems under his own definition, rather than counterexamples refuting the hypothesis

herbert-simonconnectionismphysical-symbol-systemai-historyhistory-of-ml

Simon engaged connectionism directly, and repeatedly, late in his career — not by refuting it, but by arguing it belongs inside his own framework rather than outside it. In "Situated Action: Reply to Reviewers" (Vera & Simon, Cognitive Science, 1993), responding to critics of physical-symbol-system cognitive theory, the authors discuss the "Navlab" road-steering connectionist network at length and conclude that its trained weight-pattern — which "represent[s] (denote[s]) different curvatures of the road" and is then read out to steer the wheel — "satisfies our definition of symbol." Addressing the dispute directly: "This does not, however, make it a nonsymbolic system."

Two years later, in "Artificial Intelligence: An Empirical Science" (Artificial Intelligence, 1995, pp. 104–105; source_url: https://ic.unicamp.br/~wainer/cursos/2s2006/epistemico/simon-ia.pdf), Simon named the dispute explicitly and staked the same ground alone:

"If we define symbols (as I have, above) as patterns that denote, then connectionist systems and Brooks' robots qualify as physical symbol systems."

Read together, these are not two separate claims but one sustained theoretical move, evidenced twice: rather than concede that connectionist networks are a rival paradigm refuting the physical symbol system hypothesis, Simon redefined "symbol" broadly enough to absorb them as a species of symbol system. See moc-backpropagation-origins.