“Mental stillness, on its own, has other things mixed in with it. It’s still because there are things mixed in with it, but it’s not aware of them. That’s why it’s still. Suppose that this foot-wiping cloth that my feet are on has a poisonous snake living under it. I can put my feet here without any fear because I don’t see the snake. But actually, there’s a poisonous snake right here. I have no idea, so I can relax, with no fear of anything. The fact that I don’t feel any fear is because I don’t know that there’s a poisonous snake right here. This is samatha: tranquility. “Who cares if there are defilements there? I feel peaceful right now.” This is called stillness of mind without the defilements being still. It’s called samatha. We train the mind to be still so that, in the next step, the defilements will be still. That’s an affair of discernment.”