Śūnyatā as a radicalization of anattā

One can easily argue that the Mahayanist concept of "emptiness" (śūnyatā) is a radicalization of the Theravadin concept of no-self (anattā). This argument isn't particularly original (for example, it's implied in Mark Siderits's Buddhism as Philosophy), but I'd like to explore it briefly. To be precise, I think we can view emptiness as the expansion of no-self to cover all things.

By all appearances, the self that Theravada denies appears to be the essence of a person. The Theravadin Anattalakkhaṇa Sutta provides two arguments, which I call the Control Argument and the Permanence Argument, in support of no-self. It's the Permanence Argument that matters for our purposes. As I've argued in my commentary on that sutta, the Permanence Argument rests on the premise that if x is you—that is, if x is your self—then x lasts as long as you. On this view, your self is whatever must last as long as you last. Hence, your self seems a good candidate for your essence. By definition, x's essence (as the term is used in present-day analytic philosophy) is the part of x that makes x be x instead of something else. Therefore, if your self is your essence, then we can neatly explain why your self must last as long as you do. (In Buddhism as Philosophy, Siderits goes further and says that for "Buddhists," the word "self" simply means the essence of a person.)

Likewise, when the Mahayanist Prajñāpāramitāhṛdaya, or Heart Sutra, calls everything "empty of essence," I think that the word "essence" has substantially the same meaning as in present-day analytic philosophy. Shortly after saying that all things are empty of essence, the Heart Sutra says that nothing exists at all. As I have noted in my commentary on this text, this apparent leap of logic makes sense if we interpret x's essence as the part of x that makes x be x instead of something else. Thus defined, x's essence is what distinguishes x from other things. Hence, if all things lack such an essence, then nothing distinguishes one thing from another; the distinctions between things—and, therefore, the things themselves—dissolve. The point is not that there's nothing out there but, rather, that there's no thing out there: the division of Reality into separate things is illusory.

Because the Theravadin no-self doctrine and the Mahayanist emptiness doctrine can both be interpreted as denials of essence, we can view the latter as an extension of the former. No-self says that people lack essences. Emptiness says that everything lacks essence in exactly the same sense. In a sense, we might compare no-self and emptiness to the Christian doctrines of Christ's resurrection and of the general resurrection (though I should note that, in contrast with the emptiness doctrine, which developed after no-self, the Christian idea of a general resurrection didn't develop after the belief in Christ's resurrection; instead, Christianity inherited belief in a general resurrection from Judaism). For the Christian, the general resurrection and the future renewal of the cosmos are simply God doing for the universe what he did for Christ at Christ's resurrection. Likewise, I argue, we can view emptiness as doing for the universe what no-self did for the person.