English etymology is messy stuff. The history of our language zigs and zags through the centuries. It started off as a straightforward West Germanic language – but then along came William the Conqueror, along with his French-speaking aristocracy. The result was a blending of the Germanic language of the people and the Romance language of the aristocracy – a real mishmosh that gave us plenty of word pairs like holy & saintly, begin & commence, freedom & liberty, hearty & cordial. English also inherited some vocabulary from the marauding Danes, a dash of Latin, a pinch of Greek – it really is the goulash of languages. Nevertheless, it is possible to trace the origins of most English words, or at least the first written use of those words. The Oxford English Dictionary is the ultimate source here; it presents earliest quotations of all the words it lists. Of course, there aren’t many written records from before 1000 AD, so there are plenty of common English words whose first appearance in the written record comes after that date. For example, "apple" first shows up in a written document from 1377, even though the word is undeniably much, much older (we think that it is derived from a Proto-Indo-European word, so it is reasonable to claim that the word "apple" is, in effect, 5000 years old.) The same reasoning applies to lots and lots of other English words.
However, this essay concerns a particular group of words: logical conjunctions. These words connect clauses while specifying some logical relationship between the clauses. Here’s a table showing the logical relationships expressed by the most common English logical conjunctions:
|if||if A, then B (subjunctive)||477|
|and||A and B||685|
|or||A or B||700|
|thus||A is true; therefore B is true||700|
|so||A is true; therefore B is true||700|
|then||if A then B (subjunctive)||950|
|but||A and B (B might seem to contradict A)||950|
|therefore||A is true; therefore B (explicitly syllogistic)||1175|
|nevertheless||A and B (B appears to contradict A)||1300|
|because||A is the logical consequence of B||1305|
|although||A leads to expectation C, but in fact B results||1325|
|notwithstanding||A and B (A appears to contradict B)||1380|
|however||A and B (B limits the meaning of A)||1380|
|moreover||A, with B refining the meaning of A||1380|
|albeit||A leads to expectation C, but in fact B results||1385|
|otherwise||if not A, then B||1390|
|furthermore||A, with B extending the meaning of A||1411|
|unless||if A, then not B||1431|
This table reveals much about how logical thinking evolved over time. The first seven conjunctions, all predating 1000 AD (and probably in use long before the first quotation date) are very short words, which indicates their great antiquity. They also express simple logical connections. The eleven logical conjunctions coming after 1000 AD are longer, and they are compound words. Most importantly, they express more subtle logical nuances than the first seven. Interestingly, almost all of them appear in a span of just 131 years.
Before 1000 AD, logical thinking was uncommon, and a simple set of conjunctions sufficed to handle all the logical relationships people cared to worry about. However, in the High Middle Ages, people began to think about more complex logical situations, and they needed a larger vocabulary to express these considerations.