The world abounds with metaphysical theories--God at top of the spiritual food chain with a celestial caravan of angels, standing in opposition to an eternal hell; chakras; astral bodies; turtles all the way down.
But this should come as no surprise since most people, even scientific skeptics, subscribe to a very subtle metaphysics without even realizing it. I'm referring to the notion of a self, an 'I' that inhabits our bodies, yet is somehow distinct and transcendental to it.
Buddhism challenges the notion that there single, autonomous entity in our bodies. You can call it a self, soul, spirit, or plain old 'I'. In Buddhism, it's my insistence that there is some solid being in me that causes me so much suffering. I falsely believe that there is some unchanging subject behind my experiences, like a viewer watching a television set. Meditation and deep contemplation reveals that there is no such thing. Buddhism is not alone in this criticism; many spiritual traditions recognize the emptiness of "the self," as it is often called.
The self is the most subtle and all-pervasive metaphysics, found in every culture around the globe. Let me clarify: it's not that selves don't exist at all; it's that our notion of what it means to exist is unrealistic. If we define a self as a distinct entity that experiences the world through sense organs, that thinks and feels emotions, then yes I suppose you could say that there is no self. But that just invites another form of metaphysics--no-self--which is not the intended project of Buddhism. Substituting one ailment with another is unproductive.
It might be more accurate to say that instead of destroying our notions of the self, Buddhism revises it. Meditation reveals that selves are provisional (they don't exist as irreducible entities), social, fluid, and most importantly, conditional. Selves do not exist independently. Absolute subject--entities that experience the world and are separate from it--are fictions.
There are no subjects of experiences, just experiences.
The purpose of Buddhism's deconstruction and revision of the self is freedom, liberation from the tyrant of a false subject with all of its demands, urges, impulses, and psychological hangups. It's no wonder that people inevitably subscribe to the idea of a Creator, for God is simply a magnification of people's own subtle metaphysics about themselves. God is the ultimate self because he is modeled on people's own misunderstanding of who and what they are. Both God and the personal self reflect humanity's need for a solid, substantial subject. And God being the ultimate subject, distinct from his creation, eternal; which when we think about it, is how most people view themselves--as solid entities that are separate from their experiences.
The reality of flux and flow, of utter ground-lessness, terrifies us so much that we create complex metaphysical theories that echo our own obsession with the ultimate and most destructive one--a substantial self.