Oh, sorry. I was implicitly making the following assumptions: (0) Reactions can be quantified - assigned numerical values, roughly corresponding to our intuiti

Oh, sorry. I was implicitly making the following assumptions: (0) Reactions can be quantified - assigned numerical values, roughly corresponding to our intuition of a “positive”, “neutral” or “negative” reaction. (1) The possible reactions can be meaningfully averaged, and the result can be interpreted as a reaction value as well. So by “expectation”, I meant “expected value”, in the usual sense. If your objection is that “expectation” can't be used as this, I have evidence that suggests otherwise: (0) http://ocw.mit.edu/courses/mathematics/18-05-introduction-to-probability-and-statistics-spring-2014/readings/MIT18_05S14_Reading6a.pdf http://ocw.mit.edu/courses/mathematics/18-05-introduction-to... (1) https://www3.nd.edu/~rwilliam/stats1/x12.pdf https://www3.nd.edu/~rwilliam/stats1/x12.pdf