1.
Buddhist thought can be said to begin with the formulation of the three marks of existence. These are:

1. All conditioned things are impermanent
2. All conditioned things are unsatisfactory
3. All conditioned and unconditioned things are without self

Conditioned things here means the ordinary concrete (physical) objects of reality, and unconditioned things means abstract objects (thoughts, concepts and ideas). The physical reality is impermanent and unsatisfactory. The true nature of the physical reality as well as the abstract reality is without self (without identity or non-self). The suggestion here is that abstract objects are permanent and satisfactory.

	Impermanent	Unsatisfactory	Without self
concrete objects	O	O	O
abstract objects	X	X	O

To state this plainly, concrete objects are impermanent, unsatisfactory, and without self, and abstract objects are permanent, satisfactory and without self.

Concrete objects reside in the reality. Abstract objects reside not in the reality but “somewhere else”. I suggest this “place” is the mind. But by the above definition the mind must be permanent. If this is the case, then the mind is abstract or unconditioned, which is paradoxical or illogical.

One must now define what a mind is.

2.
A standard definition in philosophy of an abstract object is that 1) it has no spatio-temporal location, 2) it has no effects on the concrete spatio-temporal objects and locations, 3) it is imperceptible by the sense, and 4) yet, it is thinkable. This last item I think is important – it is thinkable.

Abstract objects only reside in the thinking mind. If it is not located, has no affects, and is not perceived by the sense, then whether it exists in the same way as concrete objects do or not has no consequences upon the physical reality.

The new paradox is there are objects that think affecting the reality.

The only logical conclusion therefore is instead of dealing with abstract objects, one is better off dealing with the objects that think of abstract objects. This is where Buddhism is practical and functional in its outlook.

Instead of dealing with a mind, one should deal with the object that thinks, deal with the object that does mind things.