妙法蓮華經玄義 2.159

2.159

As for illusory existence and non-existence being the conventional, and neither existence nor non-existence being the real: existence and non-existence being dual constitutes the conventional; the Middle Way being neither existence nor non-existence and non-dual constitutes the real. When the two vehicles hear of this real and conventional, they fail to understand either, and are thus like mutes and the deaf. The Mahāparinirvāṇa-sūtra says: 'When Maitreya and I discussed the conventional truth, the five hundred śrāvakas thought we were speaking of the ultimate truth.' This is precisely the meaning. With respect to this, there are also [the meanings of] according with sentiment, according with sentiment-and-wisdom, [according with wisdom,] and so on.