I'm sorry, but rationality can lead to anything. It's not a cliche. If you believe that killing all frogs is good, you can use rationality to accomplish that goal. Stalin believe collectivizing all farms and abolishing all who supported religion were good. He used his rationality to accomplish his goals. As for the above quote - Truth is reality - but people don't always agree on reality. Reality, for the vast majority of people in this wolrd, includes God and what He wants. Reason is NOT man's only means of knowledge (that is a really false statement). When I trip over a rock I didn't see, I gain knowledge about that rock without having used reason. Finally, reason can't be the only standard of truth if truth is reality. Many things are true (real) for both the rational and the irrational. Police arrest an rational man and an irrational man for the same offenses. That reality has nothing to do with rationality. That is a truth which exists regardless of the arrested person's rationality.
Think ... in reply ... Nice cliche, rationalization at its finest.
Yendu in counter reply ... I'm sorry, but rationality can lead to anything. It's not a cliche.
Think's final reply ... If rationality can lead to anything, it can lead to a rational ethics.
Your cliche is now proven worthless.
QED