I do acknowledge the fact that differentiating between good and bad is a next to impossible task due to lack of clarity in their definitions and their relative meanings. It just bothers me that the two counter parts (evil and good) , do they have to coexist? Is their differentiation possible only on the basis of the counterpart's existence?
Evil as an existential necessity - no
Some word or concept pairings are logically connected : cause and effect, wife and husband, valley and mountain. Good and evil do not appear to fall within this class because there is a third term : neutral. You cannot have a wife without there being at least at some time a husband. The existence of good is not dependent on its counterpart's, evil's, existence since a world of good without evil is logically possible. A world wholly of morally good agents is possible. And evil does not necessarily enter the picture in a world only partly constituted of morally good people; the remainder may be morally neutral, incapable of moral agency whether good or evil.
Evil as a conceptual necessity - no
But doesn't the concept of good logically imply the concept of evil in the sense that we should not know what 'good' meant if we could not contrast it with 'evil'? I don't think so : all the use of 'good' presupposes is an understanding of 'not good' as a contrast. 'Not good' does not equate with 'evil'.
Is their differentiation possible only on the basis of the counterpart's existence?
Here are some notes on how Hegel's phenomenology lays out evil as an immature state of being - a state of being which overturns itself to overcome evil.
- Primordial Evil
... while Hegel follows Augustine and Christian tradition in understanding evil as a withdrawal into self-centeredness, he wholly transcends that tradition in understanding this withdrawal as occurring from the beginning in the "externalization" and "alienation" of the Divine Being. For Absolute Being becomes its own "other," thereby it withdraws into itself and becomes self-centered or "evil"; but this is that self-alienation which leads to death, a death which is the death of the abstraction or alienation or "evil" of the Divine Being (Phenomenology of Spirit, 778–80). So it is that Hegel can understand the "Bad Infinite" or Abstract Spirit as the consequence of God's own self-alienation, an alienation which is an absolute self-alienation, and one which is the ultimate ground of all alienation. Hence even in the Science of Logic Hegel can unveil all abstract spirit as "Evil" (I, One. 3, c).
See paragraph § 356 for this quote in context.
... The Christian symbol that most clearly illuminates this question is the felix culpa or the "fortunate fall," one deeply reborn in the very advent of modernity, as epically enacted in Paradise Lost. Here, only an original fall makes possible redemption, or an apocalyptic redemption, and not only an original but a total fall, a total fall whose dialectical correlate is a total redemption. This is a symbolic core underlying Hegel's dialectical philosophy, too, for only an original or primordial self-negation or self-emptying of Spirit makes possible the evolution or self-realization of Spirit itself, one wholly alienating Spirit from itself, as the "in-itself" and the "for-itself" of Spirit become wholly divided and self-estranged, and yet this is the very condition that makes possible a reconciliation of Spirit with itself. This is the reconciliation that Hegel could know as "theodicy," and an absolutely necessary theodicy, one wherein "evil" or an absolute self-division and self-estrangement are absolutely necessary for apocalypse. This apocalypse is the absolute transfiguration of Spirit, one wholly and absolutely transcending the totality of an original or primordial Spirit, and only the self-negation or the self-emptying of that totality makes possible such an absolute transfiguration of Spirit itself.
If each "good" and "evil" are considered only expressions of energy itself, then the "two" expressions of energy are not objectively distinguishable; there is only energy, without any means to superimpose a universally understood and applicable "good" or "evil" label.
Within the realm of some "eastern" philosophy there is the concept of "divine opposites", where, again, each "good" and "evil" are still a "necessity" for the perceived "opposite" to exist as half of the single whole. Alan Watts has described such phenomenon as, paraphrasing the following; the divine playing "hide-go-seek" with itself, or the divine is a single mirror broken into
N pieces, each a reflection of the others; that is, all existence is a reflection of the same original mirror, all is divine; e.g., see Alan Watts - Life is a Game of Hide and Seek.
Where we can find definitive descriptions of "good" and "evil" or "God" and "Devil" (in the literal sense of the manifestation of living God and Devil in human or other form; for example, both a cigarette and an individual human being can be Devil), is within the lessons of the Nation of Gods and Earths, where "Devil" (manifested as human) was intentionally created by humans over the course of a period of time. Of import within the above description of God and Devil is that what appears to be God can actually be Devil, the judgment is based solely on the culture of the individual: how the individual actually lives determines if they are true and correct, or purposefully manifesting wickedness; not appearances of "good" or "evil" alone. From such a perspective, it is possible to objectively or subjectively state that some individuals are intentionally evil, cannot be civilized; that is simply who they are: devil; which would tend to eradicate confusion as to the possibility that some individuals are incapable of being anything but devil; because that is how they decide to live, by manifesting "evil" in their actions, while others manifest righteousness. A member of the Nation of Gods and Earths is best suited to describe the above philosophical perspectives, see We Are NOT Anti White Nor Pro Black. We are Pro righteousness!!!
The OP raises a question about good and evil which can be expressed as: Are good and evil vague predicates?
Wikipedia describes vagueness as follows:
In philosophy, vagueness refers to an important problem in semantics, metaphysics and philosophical logic. Definitions of this problem vary. A predicate is sometimes said to be vague if the bound of its extension is indeterminate, or appears to be so. The predicate "is tall" is vague because there seems to be no particular height at which someone becomes tall.
Even though being tall can be viewed as the opposite of being small, there is no clear dividing line to eliminate the vagueness. They are defined in terms of each other without a specific boundary. One could view each as necessary for the other.
An example of two opposite predicates that are not vague are positive and negative. The dividing line is the integer zero. A positive integer is greater than zero. A negative integer is less than zero. The existence of this bound or neutral term as Geoffrey Thomas calls it in his answer removes the vagueness for these opposites.
This clarifies the difference between a predicate that is vague or not. To decide whether good and evil are vague predicates or not depends on having a definition of them so that one is not defined in terms of the other. Each has to be defined in terms of something else that can serve as the neutral boundary between these opposites.
M. Scott Peck offers a working definition that he used for his psychology of evil: (page 43)
Evil, then, for the moment, is that force, residing either inside or outside of human beings, that seeks to kill life or liveliness. And goodness is its opposite. Goodness is that which promotes life and liveliness.
With this definition one can see that even though good and evil are opposites, they are not defined in terms of each other, but in terms of opposite actions taken toward "life and liveliness". The bound of each of their extensions is determinate. They are no longer vague. Neither is necessary for the other to exist. All that is necessary for either is life and liveliness.
Peck, M. S. People of the Lie. Simon and Schuster. 1983.
Wikipedia contributors. (2019, June 13). Vagueness. In Wikipedia, The Free Encyclopedia. Retrieved 18:39, June 29, 2019, from https://en.wikipedia.org/w/index.php?title=Vagueness&oldid=901598265
the difference between good and bad, or in this case, good and evil, one could argue is there one without the other? can you say something is good if there wasn't a counterpart which defines the opposite, it's like Light and Shadow, light creates a shadow, shadows only exist because of light.
Good and Evil are both mere evaluations of actions, if there was no good in the world, there would be no evil, for there would be nothing that would evaluate an action as evil, it would merely be normal.
For most things, counterparts are always needed, light & shadow, good & bad, yin & yang, hot & cold, light & heavy, tall & short, wide & thin, Lucky & Unlucky, everything has a counterpart, it's the only reason why they can be defined as something, nothing would be tall if nothing was short, nothing would be light if nothing was heavy.