In discussions about the meanings of words I often find participants bring up the etymologies as though they are conclusive deciding factors.
On the other hand there is concept of the "etymological fallacy" as discussed in Wikipedia.
The etymological fallacy is a genetic fallacy that holds that the present-day meaning of a word or phrase should necessarily be similar to its historical meaning. This is a linguistic misconception, and is sometimes used as a basis for linguistic prescription. An argument constitutes an etymological fallacy if it makes a claim about the present meaning of a word based exclusively on its etymology.
An etymological fallacy may involve looking for the true meaning of words by delving into their etymologies, or claiming that a word should be used in a particular way because it has a particular etymology.
Which is true? Or is the truth somewhere between? If words change over history how relevant is their origin to their current meaning? If the etymology of a word is a trump card which can settle debates about correct usage of words, does this mean words cannot in fact change over time?
Best Answer
The etymological fallacy does not state that knowing the etymology of a word will lead you to misunderstand its present meaning, it merely states that the original meaning is not necessarily systematically equated to the present meaning which, on the face of it, seems a fair statement.
That is however a reductive use of the word etymology itself.
Etymology cannot be reduced to the original meaning of a word (if there ever was such a thing – words themselves having a life of their own). Instead it has to be envisioned as the whole path that leads from former meanings to present day meanings. It is not a static snapshot taken at an arbitrary point in the past; it is, as much as one can reconstruct it, the whole history of how words and cultures interact with each other to lead from stems to words and meanings. It is a dynamic thing leading to the present.
Let's take just one example: to tally. If you look it up online in the free dictionary, you will discover a whole list of apparently unrelated meanings such as:
The way these seemingly unrelated meanings are actually connected becomes glaringly obvious if you know the etymology of the word: The base meaning of a tally is "a tick marked with notches to indicate amount owed or paid" (see French une entaille).
In the old times, people would keep counts of what they owed to each other by dividing a stick in two pieces and each time a new debt was contracted a new notch (a tally) was carved into the reunited pieces. Each party would keep its own piece and, every now and then, accounts were settled with the two pieces matching. Because two different sticks can't be broken in the same way, there was no possible argument.
This is the kind of gem etymology brings to the knowledge of a given language.