A civilization is any society characterized by the emergence of complex systems on top of the more basic cultural traits of a linguistic tradition, religious-ethical codes, and agricultural sedentarism. Namely: a writing system, a legal system, governments and urbanization.
The Western Civilization Index formalizes the above criteria and objectively evaluates countries according to their "Westerness", as follows:
- Language: Romance or Hellenic language majority. Half a point awarded if at least 33% of the population speaks them. The next increasingly-inclusive obvious choice would be to consider all Indo-European languages, according to linguistic philogeny. This entails the fact that Greek is closer to Armenian and Albanian than it is to Latin, and that Latin is as close to Greek as it is to Persian and Sanskrit. Since the whole Indo-European family is evidently too wide for Western culture, we selected the core languages on which Western literary and philosophical tradition is based. Similarly, the writing traditions associated with other Indo-European branches, such as Germanic runes, have had no lasting impact on Western civilization.
- Writing: Predominance of Latin, Greek or derived (e.g. Cyrillic) script, used as an alphabet proper (phonetic writing). If used more as an abjad or logograms (as in contemporary English), we consider it as defeating the purpose and only award half a point, for pedigree. If script is eminently phonetic but comes from a different tradition (as in Korean Hangul), we also recognize that with half a point.
- Law: The clear contender for a Western legal system is so-called Civil Law, which traces its roots to Roman law, and was later influenced by Enlightenment reforms which spread via the Napoleonic code. By contrast, Anglosaxon law and Sharia law have completely different origins. Half a point awarded when Civil Law is mixed with at most one different legal system.
- Democracy: Roughly speaking, the country has tended towards democratic forms of government (any kind of democracy, parliamentary monarchy included) over the last few decades; as measured for instance by different democracy indices. Half a point awarded for flawed or developing democracies.
- Religion: Catholic or Orthodox historical background, or outright majority in the present. Half a point awarded for a minimum of 33% of the population. This combination turned out to be the most principled criterion. We obviously want to avoid religious sectarism by limiting Western culture to a single branch of Christianity. While a "Catholic or Protestant" ticket sounds like the obvious choice, an objective cultural comparison reveals that such a pair doesn't minimize cultural dissonance, generally speaking. By contrast, although the schism between Eastern Orthodoxy and Catholicism is older, both remain closer to one another, for instance in terms or rituals, theology, their preference for communitary values, and even in architectural choices.
- Urbanism: Predominantly built in masonry, with an emphasis on public architecture, as received from the Greco-Roman urbanistic style which is eminently characterized by agoras, forums and the more recent variants: squares and plazas. Half a point awarded if at most one of the following is missing: Majority of constructions built in masonry (e.g. not wood). Public architecture about as prevalent as in, say, Italy or Spain. Prevalence of European styles (e.g. not Mesopotamian, Khmer or Tiwanaku).
The final score is the bare average of the above, expressed as a percentage.