"Meaning?"
"Meaning that I could define left from right to any semi-intelligent human being who was aware of the environment in which we live."
"For example?"
I groped for an example and said, lamely, "Well, there's the weather rule, valid for the northern hemisphere. When the wind is blowing on your back, the left hand points to the low pressure center."
"Okay. But how about Venus? Astronomical information, I mean."
I shook my head.
"Why not?" he demanded. "If we face north, the sun rises on our right, doesn't it?"
"Yes. Even in the southern hemisphere."
"Well, then. So it doesn't make any difference which hemisphere they're in."
"You're correct. But you're also making the assumptions that Venus rotates on its axis, that the axis is aligned parallel to the Earth's and that the direction of rotation is the same."