 (3) A similar discussion rages today, but begins with a background assumption of multiple realization. It is thought to be highly implausible that belief in a particular proposition, or desire for a particular state of affairs, is identical with the same state of a brain (or a part of a brain) in different people, or even in the same person at different times. Instead, the same belief or desire is taken to be “realized” by different neural structures or states of activation on different occasions.