COUSCOUS

Truth is measurable.

DJexs

You could take it a step farther and say nothing you see is real. Everything in the past has already happened and is gone therefore it is not real. Everything in the future has yet to come and therefore is not real. The only real thing is the present. The input your brain get from your eyes takes time to travel therefore everything you see is slightly in the past, making it unreal.

You should read Zen and the Art of Motorcycle Maintenance. It deals with the meta physics of quality and truth.

Relapse

By that logic you can't trust anything you see either. How do you know you're not a brain in a jar being stimulated by electric probes? You need to draw the line somewhere. Saying the country of Ireland might not exist just because you've never personally been there to see it is a pretty ridiculous statement.