Scientific methods is a product of reason, a lot of things are products of reason. Rationality is something far more fundamental, and it is absolute. Rationality is to be open for the possibility that you are wrong, even about that which has been proven by reason. Irrationality is the opposite, to consider something that cannot be proven as an irrefutable fact. Rationality employ reason to arrive at what is right or wrong, what is proven and what's not. The rational mind is open to the possibility that what is proven can be disproved, exactly because it is a rational mind, for if something that is proven, is proven to be falsely proven, then that has to be enough for the rational mind. The irrational mind take something that is not proven, and tries to force reality to work according to said something being right, this is called faith. The rational mind can believe things to be proven, or just believe in general, but will not try to force the belief into existence like the irrational mind would, adapting life to reality through what one think is proven is not irrational though, not having doubt about what one think is proven is. Organized religion is a product of irrationality, reason may have been involved in its production, but it was probably ignored selectively too. What seems reasonable may change with the times, the subjective side of humanity at play, reason itself though, the more objective root of what that is, must be abandoned at some point to reach irrationality. Edit: I'm open to me being wrong about this, as I believe it to be right, but not as an irrefutable fact, because then I would have to consider myself irrational because of it. ^^ A lot about humanity and modern society is irrational, we are not perfect beings, we are simply trying our best to employ our imperfect reason.