In article ,
Thomas Borchert wrote:

Faith by definition is irrational.

by what definition?

Uhm, any. Any that deserves the label "definition" in the sense
accepted by the majority of people.

that's circular.

From Websters (and ignoring definitions related to math - i.e., rational numbers)

Rational: 1 a: having reason or understanding b : relating to,
based on, or agreeable to reason.

Reason: a statement offered in explanation or justification ...
a sufficient ground of explanation or of logical defense.

Irrational: not rational. lacking usual or normal mental clarity
or coherence. not govern by or according to reason.

I guess you don't think Websters has the definitions correct.

--
Bob Noel
no one likes an educated mule