Yogācārabhūmi Śāstra (11)

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: The encounter of altered conditions (anyathā-pratyaya-samavāya) means that when there is contact conditioned on pleasant feeling, at the time one should be experiencing pleasant feeling, one instead encounters contact of painful feeling; when there is contact conditioned on painful feeling, at the time one should be experiencing painful feeling, one instead encounters contact of pleasant feeling; when there is contact conditioned on neither-painful-nor-pleasant feeling, at the time one should be experiencing neither-painful-nor-pleasant feeling, one instead encounters contact of pleasant feeling or contact of painful feeling. Furthermore, a person with greed may encounter the condition of anger: on one side the afflictive entanglement of greed ceases, while on the other side the afflictive entanglement of anger arises. Likewise, a person with anger and delusion will encounter conditions for the arising of afflictions other than anger and delusion; it should be understood in the same way. Similarly, when the eye consciousness is presently manifest, one will encounter the object conditions of sounds, smells, tastes, and tangibles. These are the eight kinds of conditions of alteration. All alterations of conditioned phenomena, whether material form or immaterial, arise from these eight kinds of conditions; apart from these, there are no others, neither more nor fewer.

Here, "altered" (异) means change: when the encountered condition changes, the cause changes, and the result changes accordingly. The alteration of causes and conditions falls broadly into these eight kinds, though subdivided there may be many more. Because conditions change, there is impermanence; because results change, there is also impermanence. The alteration of causes and conditions fully and completely demonstrates impermanence.