The intrinsic value of an episode of pleasure, e, is equal to the number of hedons of pleasure contained in e. Every person is ultimately motivated only by the desire for pleasure and the fear of pain.
Psychological hedonism is true.
If psychological hedonism is true, then SSH is true. Therefore, SSH is true. If SSH is true, then a person who lives like a contented oyster has an outstandingly good life. It's not the case that a person who lives like a contented oyster has an outstandingly good life. Therefore, it's not the case that SSH is true.