Parmenides: Whatever the subject of your hypothesis, if you suppose that it is or is not, or that it experiences any other affection, you must consider what happens to it and to any other particular things you may choose, and to a greater number and to all in the same way; and you must consider other things in relation to themselves and to anything else you may choose in any instance, whether you suppose that the subject of your hypothesis exists or does not exist, if you are to train yourself completely to see the truth perfectly.