No kind of strict paring between list entries across from each other on the right and left is intended here. Rather, we should notice three things. (1) All of the putative objects and phenomena on the left-hand under the heading RIGID are elements of the universe that are firm and unchanging, and their existence seems to entail a kind of immutability of reality; the world cannot be otherwise. (2) Those putative objects under OPEN, by contrast, seem indeterminate and loose, and their existence demands recognition of alternatives; the world can be otherwise. (3) It is common and quite attractive to believe in the existence of many of the elements on the left and on the right simultaneously, but it seems clear that the implications of that belief are often contradictory, entailing that one and the same piece of reality both can be otherwise and cannot be otherwise in the same way at the same time. In short, certain mixtures of these elements, right and left, are nearly irresistible parts of our total outlook on the universe, but unfortunately they seem to yield contradictions. Not every pairing of items yields a paradox, e.g., 1 and 8 do not. There can be both necessity and contingency in the world. The reader is invited to consider, however, just how many left-right pairings from these lists do seem both attractive and impossible.