Why doesn't the prefix "in" in "invaluable" mean "un-" as in other adjectives? [duplicate]
Possible Duplicate:
Where did prefix exceptions originate?
- efficient
- accessible
- consistent
- articulate
- considerate
- conceivable
- convenient
- inefficient
- inaccessible
- inconsistent
- inarticulate
- inconsiderate
- inconceivable
- inconvenient
However valuable to invaluable sits alone, like a trap, not merely an inconvenient irregularity but seemingly almost inconceivable that it's not a deliberate inconsistency, causing an inconsiderate degree of inaccessibility for the inarticulate. So English is even more inefficient and inaccessible than it would otherwise be.
Or is there a logical reason why invaluable doesn't mean unvaluable?
Solution 1:
The reason for the prefix in- in invaluable is that it originally meant simply "impossible to value". It has somehow acquired the more specific meaning that it is impossible to value because its value is infinitely high. So there is no illogicality here.
Cf. innumerable, "impossible to count (because the number is infinite)", immense, "unmeasured (because it is too great to be measured)", etc. etc.
When you think about it, it is not even the word invaluable that has shifted in meaning the most, but rather valuable: it evolved from "capable of being valued" to "capable of being valued highly (because its value is high)". It is mostly the shift in the meaning of valuable that pulled the former opposites together, though I concede that invaluable bears some of the blame too.
Cf. numerous "having a high number", instead of simply "having a number", etc.
Solution 2:
There is no inconsistency. "Valuable" means "having a value (which can be calculated)". "Invaluable" means "having an incalculable (enormous) value". The prefix "in-" refers to the calculability, not the magnitude, of the value.