These give rise to those,
So these are called conditions.
Nāgārjuna, Mūlamadhyamakakārikā (I: 5)
Pratītya-samutpāda (dependent origination) is the Buddhist alternative to a theory of inherent causality. It recognises the everyday experience of regularity and correlation without investing philosophical capital in an ultimately real force, or power, linking essential causes to necessary effects. In other words, causation, from a Mādhyamikan perspective, is empty; and as such we talk of conditions. As Garfield says in Dependent Arising and the Emptiness of Emptiness:
To assert the emptiness of causation is to accept the utility of our causal discourse and explanatory practice, but to resist the temptation to see these as grounded in reference to causal powers or as demanding such grounding. Dependent origination simply is the explicability and coherence of the universe. Its emptiness is the fact that there is no more to it than that.
(Garfield, Dependent Arising and the Emptiness of Emptiness, Ch.2)
It may be "simple" but I think the "explicability and coherence of the universe," and/or lack thereof, is the undercurrent that has pulled all the thinkers into an ocean of mythological, philosophical and scientific creativity. Causality is a major product of this creativity and before examining what it means to reject it, and how and why, I think it will be useful and interesting to investigate its historical development and variation to provide some background, shared and diverse, to the development of pratītya-samutpāda. This will be the main focus for the next couple of weeks.