Perception is as perception does. 

Most lies have a rational flavour. I mean they are contrived consciously and cognitively and with those credentials rational lies essentially find themselves in the territory of real perceptions. They are false-real perceptions rather than true-real perceptions but nonetheless they are real perceptions. Stated another way, they are perceptions we expect somebody else to believe…we present them as we present what we believe to be the truth.

What a tangled web we weave when first we practice to deceive. And, isn't 'tangled web' a good metaphor for irrational truth? And, don't rational lies make good fabric for the construction of tangled webs? 

Lies and other trickery - part of the truth of the human condition. [Egos, possessing such power....so interesting.] So, it would be irrational to set the liar's bar too high, for others or for ourselves. 

Now, to a degree, the reverse is true - rational truths can be irrational lies. It's a matter of paradigm and perception. As the saying goes, "One man's trash is another man's treasure" or perhaps better still vice-versa, "One man's treasure is another man's trash". Galileo and Marconi come to mind.