It is impossible for us to know the reactions of beings constituted in a different way. It is, however, reasonable to think that in the same world ... different worlds are perceived by different beings according to the nature of their respective organs of perception.
... Does that mean that in absolute truth our senses have made contact with a real horse, a real apricot, etc.? There is no proof of this, for the only existing proof depends on the evidence of the senses ...
... We cannot presume any thing more than the existence of a stimulus which has caused the sensation that we have felt, a sensation which we have interpreted in our own way, adding to it images of our own invention.
Should we then believe that we have been taken in by a pure mirage? Not entirely. Probably the stimulus corresponds to something, but this something, that is to say the object of some kind with which one of our senses has made contact, remains unknown to us.
The Secret Oral Teachings in Tibetan Buddhist Sects