AtD translation: beyond reason

[Mike Jing]

P433.31-35   Lindsay shook his head at the tableau of chemical debauchery
before him. For a terrible moment, he was certain, beyond reason, that none
of these figures were his real fellow crewmen at all, but rather a
ghost-Unit, from some Abode he wished never to visit, resolved on working
him mischief, who had been painstakingly, intricately masked to look like
Chums of Chance.

What does "beyond reason" mean here?