The content is based upon comparison of various courses given in the University of Ghent and other reliable academic sources. The whole was first (in about four year's time) elaborated by the author and eventually, where needed, adjusted and corrected by specialist-supervisors. More specifically, Katrien De Graef (M.A.) specified the selection and spelling of Jewish names and movements; Jo van Steenbergen (M.A.) for Islam; for Eastern traditions Prof. Bart Dessein (Ph.D.) and Ann Heirman (Ph.D.). Keys to the structure are the movements and main periods (e.g. Renaissance, Dadaism, Scholasticism), along with their representatives and important publications. Even with thousands of names and subjects, this is still inevitably merely the top of what there is to show. For each historical person mentioned there are, so to speak, ten left unmentioned. A debatable twilight zone of personalities who deserve to be mentioned is inevitable, yet there is a core of important historical names that cannot be ignored. Some movements arise slowly, others are born with the publication of a single article. Often, personalities are hard to pin down : in many cases there are interactions that make it tough to radically link a name to one specific school. Some great historical names have therefore been placed in more than one area. There are obviously many more influences than can be shown, graphically or textually. And finally, although certain movements have survived time, it is not always possible to show their continuation when other developments need that space. In other words, the movements we show are either milestones or prevailing intellectual or artistic developments. Texts have been added for more clarification.

World history of knowledge? On the one hand, it might be an overstatement to call this timeline a complete world history : many Western as well as non-Western artists, scholars and intellectuals (e.g. contemporary Ukranian writers) just didn't make it because it would have meant leaving out other, more influential, Western exponents - so they were necessarily omitted for lack of space. Another reason is that, until recently, certain developments simply didn't exist in many parts of the world - for written philosophy, most of Black Africa can be an example (except for some Ethiopian philosophers), and compare e.g. the present influence of Greek mathematics to the mathematics in China. On the other hand, it would be equally biased to say the overview is only 'Western': the beginning development of Eastern religions, (with Hinduism still rather limited) Chinese letters and philosophy, Judaism, Islam, the genesis of different peoples in evolutionary perspective and so much more, all add up to a broad entirety. This widened perspective is less present in the history of art: non-Western forms of art are mentioned here and there, but are seen from a Western perspective.

The impossible twentieth century? The twentieth century (until 2001) is plainly problematic. Particularly the present is underrepresented. Not only is there a superabundance of knowledge, it is also hard to evaluate still living personalities on an intellectual or artistic oeuvre that is still in progress. Only some cases are undisputed : the influence and importance of the philosopher Jürgen Habermas, or biologists Watson and Crick are evident. Still, many other contemporary heavyweights can claim a spot on the poster, but lack of space forces us to draw a line. It is primarily important for a document like this, to show how major movements have grown over time. Thus, contemporary developments have been outlined more roughly ; any clustering or definition is only possible after years to come. In short, any subdivision of names and movements, any periodization - no matter how carefully construed - can be challenged. Simplification of our complex reality is often useful, but has its boundaries. Therefore, this tentative overview is to be considered as an aesthetic surplus to any library, and a useful study instrument.

Tom Schoepen, author and publisher of the "Timeline of evolution, culture and knowledge

Philosopher, editor in chief of the Belgian skeptics,

and graphic designer