The Pie of Knowledge
"Knowledge Is Good" - Emil Faber
The Pie of KnowledgeTM, first described in 1992, depicts an individual's theoretical knowledge base relative to all knowledge in the universe. Most people are aware of the things they know. Most have some idea of the things they don't know. We all have some idea about the things we've forgotten and our friends, family and various acquaintenances may have some insights into the things we think we know but really don't. Of course the "things you know you know" (the green slice or slice 1) is the slice of knowledge that is most useful. It is possible for things from the other three slices mentioned above to migrate to slice 1 via individual initiative and research. In other words, if you know that you don't know anything about growing roses or rebuilding a carburetor (things you know you don't know), you can go to a library or use the Internet to learn how to do those things, thereby transferring those bits of knowledge from slice 2, the purple slice, to slice 1.
By far the most interesting slice of the Pie of Knowledge is the slice called "the things you don't know you don't know," the blue slice, also known as slice 3. This slice is of unknown size for each individual. It likely comprises greater than 99.99% of the Pie of Knowledge for virtually every individual. The total knowledge of the universe is likely so vast that the sum of all human knowledge is infinitesimally small by comparision. We just don't know. What makes this slice so interesting is that the migration of information from this slice to slice 1 is purely by chance. There is no way to research the things that you don't know you don't know. There are, however, ways to improve the chances of information migration from slice 3 to slice 1, one of which is to research the things you know you don't know (slice 2). By doing this, it is likely that bits of information from slice 3 will enter slice 1. The probability of knowledge migration from slice 3 to slice 1 may also be enhanced by interacting with other individuals. Each individual has a different pie representing his/her knowledge base and through personal interaction, a certain amount of person to person "slice overlap" may take place, enhancing both individuals' slice 1.
It is vitally important that each individual (1) understand that slice 3 does exist, that is, he/she must be cognizant that there are, in fact, things that they don't know they don't know, and (2) act accordingly. The things that one doesn't know he/she doesn't know will, more often than not, come into play in some fashion to thwart the best of plans.
The two minor slices, yellow (slice 4) and red (slice 5) are self-explanatory. The "know-it-all" individual (and you probably know one or two of them) is likely to have a big red slice in his/her pie and as we age, our respective yellow slices expand, or at least so it seems. The owner of an excessively large slice 5 (the know-it-all) can be particularly dangerous to him/herself in that he/she may make ill-advised, hasty decisions based on his/her ignorance. A large slice 4 is typically more of an annoyance than a danger for most individuals.
Note that the relative size of the slices depicted in the diagram above are for illustrative purposes only. Your actual slice size may vary.
The sixth slice question.
A reader suggested that there may be a sixth slice to the Pie of Knowledge, "the things you don't know you know." While on the surface, this sounds plausible, it really is not. First, if there is something that you really know, but don't know you know it, you have either forgotten it (it resides in the yellow slice) or you have never known that you knew it. That is, there is a bit of knowledge that resides in your mind (you know it), but you can't, for some reason, retrieve that knowledge and are unaware that it is there. Using a software analogy, such a piece of knowledge would be like a block of allocated memory for which there is no pointer.
The only type of human knowledge that could exist in such a state would be knowledge that was present when the person in question was born. All other knowledge is learned. An example of this type of knowledge would be the knowledge that the brain uses to control breathing. A person may be breathing (or else he/she would be dead) and not know (or probably more accurately, be cognizant) that he/she knows how to breathe. Suddenly, it occurs to that person that, "I know how to breathe." That person now knows that he/she knows how to breathe. He/she hasn't just gained the knowledge needed to breathe, but rather has gained the knowledge that he/she knows that he/she knows how to breathe. This would be classified as spontaneous blue-green migration.
Such a spontaneous revelation would constitute a migration of a bit of knowledge from the blue slice to the green slice. On the other hand, if someone tried to remember a phone number that they had as a kid but just couldn't recall it, that phone number would clearly fall into the yellow slice. A great feature of the human brain is that it will, under some circumstances, take upon the recollection of such lost bits of knowledge on its own. In this case, the brain might take an hour, a day or several days to retrieve the missing phone number and the person will suddenly remember it. This is, of course, spontaneous yellow-green migration.
The Pie of Knowledge website was created to disseminate this model for the realms of human knowledge as well as to provide a vehicle for commentary by the owner and other interested parties.