To put suffering on the same level as impermanence and nonself is an error. Impermanence and nonself are “universal.” They are a “mark” of all things. Suffering is not. It is not difficult to see that a table is impermanent and does not have a self separate from all non-table elements, like wood, rain, sun, furniture maker, and so on. But is it suffering? A table will only make us suffer if we attribute permanence or separateness to it. When we are attached to a certain table, it is not the table that causes us to suffer. It is our attachment.
