 The standard reply to this view appeals to the intuition that illusory experience is parasitic on veridical experience. The Naiyāyika, Vātsyāyana explains that an erroneous cognition depends on a principal cognition as its basis. “This is a man” for a tree-trunk, which is not a man, has for its basis a principal cognition of a man. If a man has never been perceived in the past, an erroneous cognition of a man, in what is not a man, can never be produced (Nyāya-Sūtra-Bhāṣya, 4.2.35). A similar argument is put forth by the Advaita-Vedanta founder Śankara. He challenges Vasubandhu’s view on the ground that it is incoherent; when the Buddhists say “that which is the content of an internal awareness appears as though external,” they are