I had a couple of friends (also philosophers) down to visit this past weekend and, over coffeee one morning, we found ourselves discussing the relative merits and demerits of the popular road-trip game "20 Questions." (You can play against a computer in an Artificial Intelligence version of the game here.) Since one of my interlocutors was a Kantian and the other an Aristotelian, I supposed that they would be big fans of the game, but they each pointed out some major difficulties with the way the game forces us to describe the "things" of which we are thinking. A couple of months ago, I was on a road trip with two other (philosopher-) friends, and we also got into a big disagreement about which sorts of questions constitute strong or useful inquiries. (Our major disagreement was over the utility of the question "Is it bigger/smaller than a breadbox?") Anyway, one of the interesting things that came up in the conversation this past weekend was what counted as an "unfair" subject-to-be-guessed.
My Kantian friend had suggested that all answers to the game 20 questions had to be something that could be "imaged" in the mind, thus "ideas" were unfair answers. But I don't think that's true. For example, I think you could have the idea of "freedom" or the idea of "WWII" as an answer, neither of which can really be "imaged" in your mind, but which you could still expect people to guess in 20 questions or less. However, I argued that I DON'T think you could have "the idea of freedom" as an answer-- not because it can't be imaged, but because it is a compound idea. So, in effect, it would be like thinking of two things instead of one. (As an analog, I would say that it is unfair to be thinking of "bread and butter.")
There were lots of other disagreements, for example, whether or not any of the following attributes could be included in the answer: space (e.g., "the tree in my backyard"), time ("Benjamin Franklin at 22 years old"), ownership ("my pencil"), etc. My Aristotelian friend pointed out that, although the game suggests that what one is supposed to do is guess a "particular" from the universe of things, in fact the final answer is not very particular at all since it doesn't include some of the above attributes.
Just a cautionary tale about mixing philosophers and parlor games....