To continue the riff, we might say that the appropriate emotion for someone arguing that funding opera in fact maximises human welfare is surprise. “Now, I know you wouldn’t expect this, but amazingly it turns out that...”
Your interlocutor might believe that funding opera maximises human welfare for good reasons. But if they don’t seem to think that it’s a remarkable fact, that suggests the opposite.
This reminds me of Bryan Caplan: http://econlog.econlib.org/archives/2016/01/the_invisible_t.html
To continue the riff, we might say that the appropriate emotion for someone arguing that funding opera in fact maximises human welfare is surprise. “Now, I know you wouldn’t expect this, but amazingly it turns out that...”
Your interlocutor might believe that funding opera maximises human welfare for good reasons. But if they don’t seem to think that it’s a remarkable fact, that suggests the opposite.