Good and Evil
The basic pairs of words in moral philosophy are "good and evil" and "right and wrong" I am going to deal here with only the first of these pairs. (For the other pair, see Rights, Natural and Civil.)
The word "good" is used in a number of senses. The first is its use as an adjective, with a comparative and a superlative, as in good, better, best. This is its grading sense, in which things are judged for their exchange value. It is of little interest to the moral philosopher except in its use with regard to the summum bonum or the highest good, the best among all the real goods that are objects of desire (See Ends and Means.)
Another sense of the word is its use as a noun, when it refers to all the goods that are objects of desire, the real and apparent goods, the goods needed and wanted.
Finally, there is a sense that is unfamiliar to most individuals. This is the ontological good -- the intrinsic perfection that everything which exists possesses. Here, as Augustine tells us, a mouse has a perfection or goodness that is greater than that possessed by an inanimate stone like a pearl. Living organisms have more intrinsic perfection, than inanimate and inert things, even though the latter may have greater value in the marketplace.
In this ontological sense of goodness only God, that which no greater can be thought of, has perfection as the supreme being. Only God is perfectly good, and only complete nonbeing is absolutely evil. For everything to exist at all is to have some ontological goodness. What ever exists has some grade of perfection in the hierarchy of beings.
In the angelic hierarchy, the seraphim Lucifer has the greatest perfection among all God's creatures, and it is that which tempts Lucifer to commit the sin of pride in wishing to know God as God knows himself. With the fall of Lucifer and the other angels that follow him, Lucifer becomes Satan, morally, not ontologically, the most evil of all creatures.
This is a clear example of the separation of moral evil from ontological perfection. A morally sinful human being still has, in terms of ontological goodness, the highest grade of perfection among living organisms on earth.
Adler's Philosophical Dictionary (1995)
Great Ideas from the Great Books (1963)
by Mortimer J. Adler