What problems are there in the notion of causality?
In the second century of the Christian era, the Buddhist philosopher Nāgārjuna approached the question of causality by studying the four logical possibilities of the relationship between a cause and an effect. The first possibility is that an effect already exists in the cause (or in the set of conditions that are collectively necessary for the effect to arise). Another way of saying this is that the effect is in some sense identical to the cause, a stance that was taken by the seventh-century Buddhist Dharmakīrti, who said that the identity of a thing is nothing more nor less than the sum of the conditions necessary to bring it into being. A second possibility is that the effect is numerically different from its cause and is a new thing in the world. A third possibility is that an effect arises from a cause that is both identical to it and different from it. The fourth possibility is that the effect is neither identical to nor different from its cause, which amounts to saying that there is no relationship at all between cause and effect.
Nāgārjuna argues that the fourth of these possibilities amounts to a denial of causality and is equivalent to saying that things come into being spontaneously without any causes or conditions. It is not, therefore, an account of causality. The first possibility also turns out to be a denial of causality, since saying that an effect already exists in its conditions amounts to denying that anything has come into being. At best, it says that something that already existed continues to exist. This leaves two possibilities, the second and third. Of these, the third—that an effect is both identical to and different from its conditions—is a contradiction, so it is not really a possibility at all.
The elimination of three of the four logical possibilities leaves only the second possibility, which is that an effect is something new that arises out of conditions that precede it. This account intuitively seems right, for surely the broccoli plant that grows in the garden is different from the soil, the water, the sunlight and even the broccoli seeds that went into its making. After all, the broccoli plant can be eaten and will promote the health of an omnivore who undertakes to digest it, whereas the soil, water and sunlight cannot be used directly in that way. The broccoli has properties that none of its causes has. So why not say that an effect arises out of causes that are different from the effect itself? Nāgārjuna argues that if one says that a thing can emerge out of something other than itself, then there is nothing to prevent one from saying that a horse can give rise to a cow. After all, a horse and a cow are different, so a cow being caused by a horse would be one thing emerging out of something other than itself.
Nāgārjuna’s conclusion, then, is stated as follows: “Not from itself, not from another, not from both, nor without cause, never in any way is there any existing thing that has arisen.” (Siderits and Katsura, 2005, 135.) If nothing arises, then there can be no causality.
- Siderits, Mark, and Shoryu Katsura. 2005. Mūlamadhyamakakārikā I‒X. Journal of Indian and Tibetan Studies 9‒10, 129–185.