The Saṃgītiparyaya is the earliest Sarvastivada philosophical text that enumerates a series of contaminants (anu?aya), i.e. innate proclivities, inherited from former births, to do something of usually evil nature. This early list comprises seven such contaminants. As it is the contaminants that lead a worldling (p?thagjana) to doing volitional actions and thus to forming a karmic result (karmavipaka), these contaminants naturally also bear on the path to salvation. The gradual development of the peculiar Sarvastivadin path to salvation necessitated a gradual refinement and reinterpretation of the original list of seven contaminants. Apart from a mere technical aspect, this reinterpretation also reflects the viewpoint of the Sautrantika school of Buddhist philosophy on the nature of contaminants, i.e. their acceptance of a latent and an active state of the defilements, vis-a-vis the Vaibha?ika viewpoint according to whom no such difference exists. Within Sarvastivada literature, the H?daya treatises illustrate this philosophical development.
