So if you encounter an unknown intelligence, like I dunno some kind of extra dimensional pen pal with a wildly different biology and environment than our own... Would you be open to the possibilities:

- despite our difference we have the same kind of intelligence

- our intelligences intersect, but there are capacities that each has that the other doesn't

?

It seems like for either to be true there would have to be some place of common ground into which we could both generalize independently of our circumstance. Mathematics is often thought to be such a place for instance, there's plenty of sci fi about beaming prime numbers into space as an attempt to leverage that common ground. Are you saying there aren't such places? That SETI is hopeless?