Manfred taught me mathematical logic back in the mid 90s. It was only much later browsing functional programming topics that I discovered his language and that he had passed away.
My mate has an awesome story about providing technical support to him on campus. I hope neither he nor the deceased mind me relating it.
"Hello. Tech support? This is Manfred von Thun. My computer is not working."
"OK, no problem, do you have a PC or a Mac?"
"Neither."
<Pause>
"Neither?"
"Yes. Neither."
"Ok, what do you have, then?"
"I have a terminal which connects to the mainframe."
<Pause>
"OK, I'll be right over."
Sure enough, he gets there and there's some godforsaken yellowing text-only terminal thing with a wire plugged into some weird port he'd never seen before, presumably wending its way into the bowels of the university to some long-lost, dusty piece of big iron from computing's distant past.
My mate was incredulous. "So what do you do with this, exactly?"
"I write papers, I write programs, I make web pages."
"Web pages!?"
"Yes, web pages. But I don't believe in graphics."
In spite of his protestations about GUIs, he was eventually given a brand spanking new eMac (this was around about the time he was creating Joy). Once he saw Terminal.app, he no longer seemed particularly concerned.
Every staff member had one of those. They opened new computer labs at La Trobe in about 1995 but before that it was VTxxx terminals accessing a mixture of VMS or *nix, I believe.
I remember using vi in typesetting a paper with LaTeX before print previewing a DVI on one of the PC or Mac machines.
He was a European gentleman in a remote land with a quirky sense of humour and generous spirit; not your typical stuffy academic in tweed. :) And he had an awesome beard, long before hipsters made them fashionable!
The tribute pages below provide more insights from others.
I was studying in the mathematics department at the time, which was on the other side of the campus from the philosophy department. But there was considerable overlap between pure maths and formal logic. Godel's incompleteness theorem was one of the topics we proved and provided a good theoretical foundation for higher order logic.
Yes, Joy is amazing. I have been working through the Advent of Code puzzles with it and the code keeps coming out error-free. It delivers on Backus' idea of algebra of programs (aka "Functional Programming") in a direct and entertaining way. It also seems amenable to efficient compilation.
I'm pretty sure Joy is a kind of "silver bullet" for programming, in the sense that, as "software is eating the world", Joy will eat software.