Note that the measuring stick for utility does NOT require a common attribute of measuring sticks for length—every dollar is better to have than not, but does not need to be better by the same amount as other dollars. It’s perfectly acceptable to have a ranking of outcomes ( mushroom > pepperoni > anchovy > nothing ), with no numbers attached, and without implying that the pepperoni->mushroom upgrade is worse than two anchovy->pepperoni upgrades.
Your ordinal preferences as stated don’t answer that question—you decide by having more terms in your utility function. Assuming independence of outcome (which is NEVER true, but really handy when analyzing toys), you might be able to assign a numeric marginal value to each upgrade. Or you might just have an additional preference for certain pepperoni over 50⁄50 mushroom/anchovy. Heck, you might have a preference for certain anchovy over 50⁄50 mushroom/pepperoni (though this that uncertainty is itself negative value to you, in addition to your pizza topping valuation).
Note that the measuring stick for utility does NOT require a common attribute of measuring sticks for length—every dollar is better to have than not, but does not need to be better by the same amount as other dollars. It’s perfectly acceptable to have a ranking of outcomes ( mushroom > pepperoni > anchovy > nothing ), with no numbers attached, and without implying that the pepperoni->mushroom upgrade is worse than two anchovy->pepperoni upgrades.
How do you decide between a certainty of pepperoni and a coinflip of mushroom or anchovy?
Your ordinal preferences as stated don’t answer that question—you decide by having more terms in your utility function. Assuming independence of outcome (which is NEVER true, but really handy when analyzing toys), you might be able to assign a numeric marginal value to each upgrade. Or you might just have an additional preference for certain pepperoni over 50⁄50 mushroom/anchovy. Heck, you might have a preference for certain anchovy over 50⁄50 mushroom/pepperoni (though this that uncertainty is itself negative value to you, in addition to your pizza topping valuation).
Note that if you prefer A to B to C, but prefer “certain C” to “coinflip A or B”, then you don’t have a utility function over ABC.
You might, as in OP, have a utility function over something else. Like maybe “ABC plus a history of correctly predicting which of ABC I’d have”.