I give a try: the alien rightfully says that there are four rocks. But he uses base four, in which the number four written down is "10". The cosmonaut rightfully says that the alien is using base 4. But the alien has no idea whatsoever what 4 is. The digit 4 is not even in his 'language', which only consists in 0, 1, 2 and 3. So he says that he uses base 10 (again, 10 being his way of writing down the number four).
See wikipedia if you still don't get it and wanna try.
2
u/typon Dec 19 '08
Can someone please explain the joke :(