[Revised question]
Is there a name for expressions or sayings such as "the end justifies the means?"
After searching online I found that this expression is defined as consequentialism. But what I'm asking is whether there is a name for this types of phrase. At first, I thought it was an idiom, but by definition it is not an idiom because one can deduce the meaning from the words of the expression.
Also, after reading the many excellent comments and answers, I looked at the term proverb and maxim, but these don't seem to quite fit either because "the end justifies the means" doesn't seem to be a "general truth" in fact it is more of a moral rationalization that many people do not believe to be true.
Just to clarify, I'm not asking for definitions of "the end justifies the means" or "consequentialism"; I'm asking what are phrases such as this called, where their meaning, unlike an idiom, can be deduced from the words in the expression or saying, and where it is not a general truth (i.e. adage, maxim, proverb, etc).