Three years ago Richard Boyd died. I saw the news on a Cornell website in the middle of a working day and didn’t have time to think about it. So I didn’t think about it.

Dick Boyd. He could’ve stopped with undergrad teaching early in his life. He certainly could’ve stopped later in life. But he didn’t, because he loved it, and kept teaching to stoned, bored, dumb 20 year olds; and so I met him.

He taught philosophy of science, and was known for that, but he was an ethicist at heart I think. Really a moralist, to use an old term.

He ranged over everything (including my stuff like philosophy of language/logic & also math, which he did with Putnam at MIT) — but in all his work he was most of all humane. My favorite topic of his was, of all things, species, as in biological species.

He rejected essentialism on that. This needs clarification because no one knows what “essentialism” means anymore. Say: an essentialism about species would be like Plato’s “featherless biped” for a human—some single required property. A more sophisticated version might be something like cladistic descent—but the details here don’t really matter. He rejected all this. Instead he argued for homeostatic property clusters for all natural kinds, of which species were one type of natural kind.

With this fancy term he just meant: there are a set of features that typically occur in a set of similar individuals (where no single property is essential to define that group). Again: no single property. Instead, a member x belongs to natural kind y when x exhibits some number of the properties common to this group. The extensional limits of the group are not quite precise, and so there are unavoidable and unresolveable “borderline cases” (as a philosopher of language would say).

And that’s the whole point. His under-appreciated model has great explanatory power for the real natural world, as described by real science, where a concept like essence doesn’t meaningfully appear.

The details about species are interesting, but still secondary to what he really cared about. Dick rejected all sorts of reductive essentialism before it was cool to do so: his point about species also extended to a whole set of social kinds. This was his point.

See, Professor Boyd was a Marxist of the old school kind—the kind my Yiddish-speaking great-grandmother would’ve been alright with. On this he was most of all a realist consequentialist. I think Dick would hate whatever tweets pass for “Marxism” nowadays. His Marxism was exact, moral. Outcomes were either good or bad, and there was a fact of the matter. The literal good depended on it. Whether he was right or wrong on political outcomes is another story (or whether the good exists at all, as my anti-realist mutuals might argue): but the point is that his first-order apparatus of appraisal was finely-tuned and powerful.

His socks were always mismatched.

I was so insecure those days about what I knew in philosophy. And yet, as a undergrad, he let me teach an entire three-hour seminar about “Putnam & Natural Kinds” to his group of grad students. I did Twin Earth, then Kripke’s gold, and even dared to do some later Lewis, which confused everyone; then I doubled down and scribbled Barcan’s Formula on a blackboard for some reason. I lost the entire class in confusion, and he laughed that I had gone too far. I was terrified. Soon everyone left, and I went back to my notebook. He said I did a brilliant job, and that I should go into teaching. I didn’t, but those three hours still changed my life. I will never forget it. Some time later, when I become serious about actually doing it, he asked me: “can you do anything else besides philosophy? Do that if you can”, and he changed my life again.

Despite his exacting scientific realism, his naturalism and materialism, it turns out Dick thought a lot about religion. He knew grace as well as any Christian theologian, and he could talk gnosticism as well as he could talk physicalism.

Whether our souls live on after this life, we will never know. But I really hope his will.