En réponse à Andreas Johansson : >That as well. But how could I absolutely _know_ I can't change how the real >world works? You can't. Another point for the impossibility to assert the existence of a "real world". But then, science is nothing more than a set of assumptions and rules issued from them which *as far as we know*, and in their particular domain, work well. That doesn't even mean they are absolutely correct. Newton's laws of mechanics are well known to be just an approximation, which completely fails in many cases, but that doesn't mean that they are useless. They have their uses, in their domain. The point is, this is the maximum of certitude we can ever have in science. Christophe Grandsire. http://rainbow.conlang.free.fr You need a straight mind to invent a twisted conlang.