Yogācārabhūmi-śāstra (Eleven)

Original text:异缘会遇者。谓缘乐受触。受乐受时遇苦受触。缘苦受触。受苦受时遇乐受触。缘不苦不乐受触。受不苦不乐受时。遇乐受触。或苦受触。又有贪者会遇瞋。缘贪缠止息。发起瞋缠。如是有瞋痴者。会遇异分烦恼生缘。当知亦尔。如是眼识正现在前。会遇声香味触境等。是名八种变异因缘。一切有色及无色法所有变异。皆由如是八种因缘。除此更无若过若增。

Explanation: "Encounter with altered conditions" means that when the contact is conditioned upon pleasant feeling, at the time one should be experiencing pleasant feeling, one instead encounters contact that gives rise to painful feeling; when the contact is conditioned upon painful feeling, at the time one should be experiencing painful feeling, one instead encounters contact that gives rise to pleasant feeling; when the contact is conditioned upon neither-painful-nor-pleasant feeling, at the time one should be experiencing neither-painful-nor-pleasant feeling, one instead encounters contact that gives rise to pleasant feeling or to painful feeling. Furthermore, a person with greed may encounter conditions for anger: on one side the entanglement of the affliction of greed ceases, while on the other side the entanglement of the affliction of anger arises. Likewise, a person with anger and delusion will encounter conditions for the arising of afflictions other than anger and delusion; this should be understood in the same way. Similarly, when the eye consciousness is presently manifest, one will encounter objects such as sounds, smells, tastes, and tactile objects as conditions. These are called the eight kinds of causes and conditions of alteration. All alterations of conditioned form and formless dharmas arise from these eight causes and conditions; apart from these, there is nothing more—neither anything exceeding nor anything added to them.

Here, "altered" means "changed": when the conditions one encounters change, the causes change, and the results change accordingly. The alteration of causes and conditions can be broadly divided into these eight kinds, though finer subdivisions could be numerous. Because conditions change, there is impermanence; because results change, there is also impermanence. The alteration of causes and conditions fully and completely demonstrates impermanence.