It feels like everyone in this conversation is just choosing their own arbitrary definition of computation. The question is, why have you chosen that definition, what makes it useful? As the author points out, if rocks compute, then there is not much meaning to computation as a concept.<p>Computation in the colloquial sense refers to a sequence of events that happens inside machines that were made by humans in order to calculate some explicit mathematical results that the human operators have some interest in. I think this is a fine definition, and one that includes computers but not humans or rocks. I feel like the author erred in trying to redefine computation into some other abstract concept, muddying the water such that everyone is just talking about what &quot;computation&quot; means to them.<p>I think the real question we&#x27;re getting at is, &quot;what is the relationship between what a human brain does to solve a problem, for example moving a body into the correct position to catch a baseball, and what a computer does, which we know is executing explicit math equations to calculate trajectories, inverse kinematics, etc?&quot; Right? We&#x27;re talking about the illusion of intent, of goals, of the desire to solve problems - and as far as we can tell, rocks obviously do not possess those traits.