I don't think he was thinking of rights, thus I doubt he was thinking of things. I think he was thinking of the general concept of right.

F'rinstance, how do we know that killing someone is wrong? how do we know that it is right NOT to kill someone? (is perhaps a more apt way of putting it)

I suppose this is the right that comes from our reason and (supposedly) sets us apart from the dumb beasts. (and who said they were dumb, anyway, just because they don't speak a human language!)

Let us go in peace to love and serve the board.