The doctrine of emptiness
The Prajnaparamita sutras were a series of Buddhist philosophical texts written around 100 C.E., centering around the concept of sunyata. This word has been translated as emptiness, voidness, spaciousness, and lacking an intrinsic nature. This philosophy was not initially a departure from earlier Buddhist doctrine, but as later thinkers gave their commentaries and interpretations a new school began to emerge; the Madhyamaka.
Early Buddhist sutras describe a dualist philosophy: both relative and ultimate truth exist. Nagarjuna was a Madhyamaka philosopher who systematically argued for why this is a logically incoherent position, disproven by its own internal reasoning. Instead, he advocated for a philosophy based upon the Prajñaparamita doctrine of emptiness; which states that feeling, thought, consciousness, and form, are all equally unmanifest. While earlier Buddhist philosophers (and later Yogacara philosophers) held positions asserting some of these qualities to hold truth and others to be illusory, Madhyamaka doctrine held that all were equally illusory, non-existent, and beyond conceptualization. As Nargajuna puts it “nowhere does anything ever arise”. Siderits describes the same thing in a more easily digestible way: “there can be no ultimately true account of the nature of reality”.
Nargajuna uses many logical arguments to prove that this stance is the only defensible one. He asserts that anything that is compounded lacks intrinsic nature, and proves all things, including consciousness, to be compounded and interdependent. He also uses motion to prove that there is no ground for phenomena to stand upon that would allow it to exist. I think Nargajunas most important assertion is that even the doctrine of emptiness is something that needs to ultimately be abandoned. In the MMK he states: “Emptiness is taught by the conquerors as the expedient to get rid of all [metaphysical] views. But those for whom emptiness is a [metaphysical] view, they have been called incurable”. Emptiness is a tool that allows us to release the wrong views that shape our philosophies, but it needs to be left behind as well to arrive at the place it describes.
In my opinion the doctrine of emptiness is best described through poetry and paradox, the Prajnaparamita sutras that set off this movement are a shining example of this. Emptiness is a concept that can only be articulated indirectly, through showing what it is not. All phenomena are fever dreams we perceive to be reality, the catch being that there is no dreamer. Emptiness is the pregnant void from which all phenomena manifest and return to. By accepting this philosophy, and then abandoning it altogether, emptiness is experienced even though it cannot be found.