> If these aliens were at the same technological level as us then they would have developed their own system of logic but this could be very different from human logic.

This statement makes grammatical sense, but I'm not sure that it makes real sense. (But perhaps since "real sense is by definition "logical," maybe it doesn't have to.)

I think the problem is with the use of the phrase "system of logic." Perhaps you mean "system of thinking." If so, we don't have to go to outer space to find it. Just look at human superstitions.

It's very hard for me to imagine an alien "civilization" as "advanced" as ours whose *scientific* accomplishments are not based on the same logic, even if their everyday lives are built on the opposite of logic, which is superstition, error, magic, etc.

Logic and math appear to be part of the fabric of the universe but are only perceptible by human (or higher) intelligence. For example, one cannot persuasively claim that 2 and 2 did not equal 4 (in other than quantum terms, perhaps) in the Jurassic period, or immediately after the Big Bang even if there was no one there to perceive it.

Of course, one can *claim* that mathematical rules/laws/phenomena did not exist, but it is hard to conceive of what the evidence could be - especially since it would have to run counter (I think) to everything else we understand. And the possibility that "everything else" is wrong is remote indeed.

As they say, "anything is possible." But some things appear to be so close to impossible by any rationally coherent standard that they can be rejected as quite untrue - until communicable evidence tells us otherwise.