Almost before the ceremony was over she came close up to him and said: "Tiberius, this is illogical behaviour.

I'd have to look at the man's case file again, but illogical behavior is the only indication of an abnormal state.

He uses economic principles to draw forth the rational elements of supposedly illogical behaviors to illustrate his point.

I would hope that the creators of devices as sophisticated as these, apparently constructed of pure energy, would be beyond such illogical behavior.

Can you give us any valid reason for this illogical behavior?

There is usually a logical pattern to his illogical behavior.

Yes, Breetai was amused by the challenge of illogical behavior; it forced him to step outside his own conditioning and search for novel approaches to destruction.

And their illogical behavior.

He doesnt seem to find it odd to respond to illogical behavior every now and then.

If the situation were not so grave, Sarek would have been amused at the human's illogical behavior, so much like Amanda's.