The thing is, Dijsktra also did a lot of practical work (first Algol compiler, an OS, structured programming), so I wouldn't discount him as just a theoretician

The thing is, Dijsktra also did a lot of practical work (first Algol compiler, an OS, structured programming), so I wouldn't discount him as just a theoretician, either. I agree that they both did very important contributions, and that there's probably no way to compare their magnitude, so it comes down to personal interpretation, there's no argument there. Still, I believe the arrogance comment by Kay was douchey :)