Will can react on itself indefinitely
The good and the end is the object of the will. But the will can react on itself an infinite number of times [...]. Therefore there is an infinite series of ends of the human will, and there is no last end of the human will...
Objection 3. Further, the good and the end is the object of the will. But the will can react on itself an infinite number of times: for I can will something, and will to will it, and so on indefinitely. Therefore there is an infinite series of ends of the human will, and there is no last end of the human will.