One of the central distinctions about the nature of Knowledge in TOK is that between Personal and Shared Knowledge. Personal Knowledge is meant to refer to knowledge which has been acquired by the individual based on their own experiences, efforts and conclusions. Shared Knowledge is knowledge which is held communally, by groups which will vary in size depending on the type of knowledge being explored. For a start, I am not at all convinced that it is genuinely possible to distinguish Personal and Shared Knowledge in this way, it seems to me that the relationship between the two is so enmeshed and symbiotic that a hard and fast dichotomy should be viewed as an unhelpful over-simplification.
The vast majority of what we claim to know as individuals is more often than not the result of previously existent ideas which, in some cases, may have been dormant in our minds over many years. Those ideas will have been acquired over a very long period of time and by many different methods and an appropriate stimulus will only ‘awaken’ them and make us feel we are experiencing them for the first time. This model of learning is, of course, a very ancient one and was first proposed by Plato in the 4th century BC. In this view all learning is in fact an act of remembering what the mind already knew but had forgotten. Whilst Plao’s model is based on his concept of the Forms (pre-existent, abstract and perfect), one could adapt this to the argue that no-one has ever learnt anything new in a vacuum, all learning has a context and that context provides the basis for the ‘new’ discovery, without it so-called individual knowledge couldn’t exist. After all, even someone on a desert island is still acquiring information from that very specific or limited context. However, history does provide countless examples of individuals who seem to have thought not only genuinely new things but also ideas quite contrary to the prevailing status quo, Copernicus and Einstein being of course notable examples. On the other hand, even they were making use of pre-existent data and methods even if only to oppose them.
As for Shared Knowledge, one could very well argue that it should not really be regarded as Knowledge in any real sense of the word. The validity of any piece of knowledge would normally be established on the basis of whether it is justified by argument or evidence. Shared Knowledge is by definition knowledge held by more than one person at any one time, identifying the source or sources for this commonly held perspective is no easy matter which in turns makes testing the validity of the knowledge held even more difficult. Moreover, the piece of knowledge held by any group of any kind is bound to take different forms as each individual member imprints their own stamp on the material, their own take on its value, their own interpretation of its meaning etc… Establishing whether any piece of knowledge can qualify as Shared Knowledge seems to me to be an impossible challenge. Much better to think of most of it as common assumptions or accepted beliefs. Having said that, all groups do operate on the basis of agreed facts, values and goals; to regard oneself as being a member of group x or y, is in part to adhere to a specific world view which is based on a common perspective. The degree to which this can objectively be called Knowledge may differ depending on the size of the group or the type of knowledge shared, although in my view in most cases this is a step too far.
Shared Knowledge may therefore not be knowledge at all and since, arguably, all Personal Knowledge is based and dependent on it, not only is the distinction between the two unhelpful and misleading, but neither may be any kind of knowledge at all.