I was discussing with a friend today the problem of dream pens. In Tibetan Buddhism, there are generally recognized four Indian schools of Buddhist thought: Vaibhāṣika (Detailist), Sautrāntika (Sutrist), Cittamātra (Mind-Only), and Madhyamaka (Middle-way, which has two sub-schools, Consequence and Independent). Madhyamaka Prasangika view is that all phenomena are dependently-arising and thus empty of inherent existence.
Sure, that sounds fine, say the Detailists. But you have a problem: what, in your philosophy, is the difference between a real pen and the dream of a pen? If, for example, I dream that I write a letter with my pen and leave it on my desk, when I get up will there be a letter there?
No, of course not. So then there must be something real (inherently existing) about the real pen, because I can write a letter with that pen. So:
Consider a dream pen,
I can’t write with it,
Because when I wake up it doesn’t work.
True or false?
So, the only way to know is to run the three tests. Test #1: Is there a relationship between #1 (the subject) and #3 (the reason)? Well, it looks like it: when I wake up, it’s true that the dream pen will not have written anything.
But think carefully, is that what a dream pen is supposed to do? In other words, is the function of a dream pen to write real letters?
Put that way, of course not. The function of a dream pen is only to write letters in a dream. So then is it true that the dream pen didn’t work? No, of course not–it worked exactly as expected: the dream pen wrote a dream letter (which is gone, as I would expect, upon waking).
So the answer is rtags ma grub (tak ma drup): your reason is not established, and this syllogism is not true.
Because the functioning of anything is also (in part) a construct of the mind, dependent on our seeing and thinking of it as we do. Functioning itself has no more inherently existent than any other thing that we can think of.