"What is the mind? It is nothing other than what is merely imputed by the mind, by the thought. In other words, because of the reason that the base—this formless phenomenon that is clear and perceives objects—exists, mind is merely labeled by the thought, and believed in. Because of this, thought makes up the idea, the concept, the label, "mind," and then believes in what is merely imputed by thought. Therefore, what the mind is, is extremely subtle. It does not exist in the way it normally appears to us. In reality the mind that exists does not exist in the way that it normally appears to us, in the way we normally apprehend it, as a real mind existing from its own side, an inherently existent mind. It is not that.
This formless phenomenon whose nature is clear and able to perceive objects, this is the base. Depending on this base, mind is labeled, so mind is the label and that phenomenon is the base to be labeled. Therefore the base and the label "mind" have to be different; they cannot be one thing. There is no way that the base to be labeled and the label can be one. If this particular formless phenomenon that is clear and able to perceive objects were the label "mind" there would be no point in labeling mind? Why would you label "mind"? There is no reason to label "mind" on the mind. This would become endless. You would label mind on the mind, then you would have to label mind on that mind, then again you would have to label mind on that mind. It would become endless. There is no purpose in doing this---"
Lama Zopa Rinpoche
The Ultimate Nature of the Mind
Adelaide, Australia, 1991