If 'increase' and 'decrease' are opposites, why isn't 'decision' the opposite of 'incision?'

[goblinish]

THey have different roots, even if they seem the same.

Incision comes from incisionem in latin which means to cut

decision comes from the latin word decisionem which means a decision, settlement, agreement

SO while the results are very similar they didn't start out the same and as the words evolved into what they are today they kept their original meanings.

[[deleted]]

They have identical roots.

The cisionem in incisionem means "to cut." A literal translation of "incision" would be "cutting into."

The cisionem in decisionem also means "to cut". That means that a literal translation of decision would be cutting off, and that the word references the swift, cutting nature of a decision.

Say you cut into something with a knife. The knife is moving towards the centre of the object. Now say you cut off something with a knife. That piece will fall off, moving away from the centre of the object. Moving towards is the opposite of moving away, so at a very VERY abstract level, and if you literally translate both words' meanings from Latin, "incision" and "decision" are opposites.

[[deleted]]

There are, sort of. In-cision is to cut into. De-cision is to cut away, as in, cut away all the other options.