Ananda said: "I have always heard the Buddha when teaching monks, nuns and male and female devotees say: When the mind stirs all sorts of things are created and then all kinds of mind appear. I now think that the substance of (my) thinking is the nature of mind which arises when it unites with externals and which is neither within nor without nor in between.
The Buddha said: You have just said that because phenomena are created, all kinds of mind appear when uniting with them. So this mind has no substance and cannot unite with anything. If that which has no substance can unite with externals, this is union of the nineteenth realm of sense with the seventh sense datum(No such union can occur hecause there are only eighteen realms of sense and six sense data). This is sheer nonsense. If the mind has substance, when your hand grasps your body, does your mind feeling this (touch) come from within or without? If from within, you should see what is in your body and if from without, you should see your face.
Ananda said: It is the eyes that see and the mind that knows is not the eyes: to say that it sees is wrong.
The Buddha said; If the eyes can see, when you are in a room, do you see the door (outside)? Those who are dead and still have eyes, should see things if they still see, how can they be dead?
Ananda, if your knowing mind has substance, is that substance single or manifold? As it is in your body, does it spread to every part of it or not? If it is one substance, when you grasp a limb, all four should feel that they are grasped; if so there would be no grasping (of any particular limb). If there is, the contention of a single substance does not hold good. If it is a manifold substance there should be many persons; then which substance is yours if it spreads to every part of your body, this is the same as in the previous case of grasping. If it does not spread, then when you touch your head and foot at the same time, while your head feels that it is touched; your foot should not, but this is not so. Therefore, your contention that the mind arises where there is union with externals is groundless.