Newell and Simon claimed symbols are necessary and sufficient for intelligence

In their 1975 ACM Turing Award lecture, “Computer Science as Empirical Inquiry: Symbols and Search” (published in 1976), Allen Newell and Herbert Simon stated the physical symbol system hypothesis: “A physical symbol system has the necessary and sufficient means for general intelligent action.” In plain terms, they claimed that the right setup of symbols and rules for manipulating them is all that is required for intelligence, the founding bet of symbolic AI.