 A radical transformation in metaphysical views in China followed the introduction and incorporation of Buddhist philosophy, a process that began in the 1st century CE. On the surface, one might think that Buddhism opposes metaphysical speculation. In the famous parable of the arrow, the Buddha compares a student insistent on metaphysical speculation to someone who has been shot with a poisoned arrow but refuses to be treated until he knows who shot the arrow, why they shot it, where the arrow came from, and so on. The point is that we know that the central problem in life is suffering and we know that the cure is the elimination of self-centered desires. Nonetheless, Buddhists commonly claim that one can be released from such desires by seeing reality as it truly is. The truth to be realized is that there is no self as an independent and lasting being. Much of Buddhist philosophy can be read as a sustained attack on any kind of substance-based metaphysics. The existence of substances (and thus of the self as a real and lasting thing) requires three things: ontological separation between things (making the self distinct from others), internal unity (so that it is one self), and sameness over time (so it remains the same self). Buddhists attack all three of these, arguing that things are interconnected, lack intrinsic unity, and change endlessly. Their arguments invoke two of the main principles of Buddhist metaphysics—impermanence (anitya/wuchang 無常) and dependent co-arising (pratītyasamutpāda/yuanqi 緣起).