成唯識論演祕 4.165

4.165

問：若依自義，三依並無，既假同他，何但有二？《俱舍頌》云：「心、心所由四，二定但由三。」三者四中除所緣緣，故不唯二。

Question: If one relies on our own tenet, none of the three bases exist; since [the text] hypothetically agrees with the other [school], why are there only two? A verse of the Kośa says: 'Citta and caitasikas depend on four [conditions]; the two attainments [of cessation] depend on only three.' 'Three' means excluding the objective condition from the four, so it is not only two.