Common preference vs critical preference

Popper came up with the idea of a critical preference and I am going to contrast this with common preferences. In Section III of the Introduction to “After the Open Society”, Popper writes:

For we can discuss our various competing assertions, our conjectures, critically; and the result of our critical discussion is that we find out why some among the competing conjectures are better than others.

Accordingly I agree with the optimists when they say that our knowledge can grow and can progress; for we can sometimes justify the verdict of our critical discussions when it ranks certain conjectures higher than others.

This idea is wrong as first pointed out by Elliot Temple. Critical discussion does not rank ideas. A critical discussion attempts to solve a problem and either accepts a particular proposal as a solution to a problem or rejects it. There is nothing in between. Sometimes you might attach a number to various solutions of an idea and choose the one with the one with the highest number or the lowest number or choose in some other way related to the number. For example, you might compare cars to see which uses the least amount of petrol when driving in a city. You may list the cars in order of miles in city per litre of petrol. But you actually choose the one that has the highest number of miles per unit of petrol and reject the rest. Whatever way you list the cars you accept one and reject the rest. So the idea of a critical preference as a ranking of ideas after a critical discussion is wrong. When people think they are ranking ideas they are actually doing something like munging together lots of different contexts in which different ideas are useful, or they are choosing according to some unstated and uncriticised criterion. This means that criticisms that might improve your ideas are ignored or are not generated at all, which is bad.

A common preference is an idea that all of the people involved in a dispute prefer to their original position. To get a common preference that you must answer all of the criticisms of the idea that is adopted. If you don’t then it doesn’t mean anything to say that the adopted solution is preferred to other proposals since they both have the same status: they have both been rejected. You don’t rank the suggestions. Each suggestion is either accepted or rejected.