"There are many monisms. What they share is that they attribute oneness. Where they differ is in what they target and how they count. … Existence monism targets concrete objects and counts by tokens. This is the doctrine that exactly one concrete object token exists. Priority monism also targets concrete objects but counts by basic tokens. This is the doctrine that exactly one concrete object token is basic, and equivalent to the classical doctrine that the whole is prior to its (proper) parts. Neither existence nor priority monism is accorded much respect in contemporary metaphysics, nor are they always properly distinguished. Indeed, the tradition associated with these doctrines has long been dismissed as being somewhere between obscure and ridiculous. But there are serious arguments for monism. Priority monism may especially deserve serious reconsideration, of a kind that it is only now beginning to receive. … there are of course other historically important monisms, including substance monism. Substance monism targets concrete objects and counts by highest types. This is the doctrine that all concrete objects fall under one highest type (perhaps material, or mental, or some neutral underlying type: here the way divides)."