They have juxtaposed the wrong part of "transcendental" with "rational" to create "transrational" in an attempt to justify their belief in transcendence. Similar mistake to "posture-pedic".
Karsten is using "transrational" in its correct form. "Irrational" would simply mean "without rationality". "Transrational" is used to imply there is a rational process present; however, it has changed to the opposite of "normal" rationality, cf. [link|http://dictionary.cambridge.org/define.asp?key=84393&dict=CALD|http://dictionary.ca...y=84393&dict=CALD]