[jordan_curve]

He made novel contributions to computability theory. The first person to show that one-dimensional cellular automata could be turing-complete.

That being said, he’s very much a crackpot nowadays. Being sane in the past does not imply you will be sane in the future, no matter how significant your list of accomplishments.

[thwayunion]

His results on cellular automata are clearly solid contributions. Any academic would be proud to open a whole line of inquiry. I understand that he's also done good work in Physics.

I was just surprised to see this particular result about propositional logic in particular highlighted because, as a logician, I really don't care :)