This meditation analyzes the difference between a quality, and something that is characteristic of that quality. In Tibetan this is known as “chi-jedrak.”
A deep grasp of the relationship between these two things is a trigger for seeing emptiness directly.
How to Perform the Diamond Cutter Meditation?
Why, when I look at that Ford Tempo outside, do I think “That’s a car”?
What about it has the quality of “car-ness”? Is the car-ness in the four wheels, or the engine, or the bumper? No. Is it somehow hovering in the air around the whole thing? No. I am projecting the idea of “car” onto that hunk of metal. Really the only cars that exist are in my mind. “Car” exists in my mind — an image of my mind. It is a quality, and this thing in front of me is characteristic of that quality.