A) I've sometimes heard people say that Evil is simply the absence of good, but others say that Evil is a definitely existing force.
What do you say, and what should Christians believe?
The historic, orthodox Christian view is a firm rejection of cosmic dualism: that there are two opposing forces at work, Good and Evil. Good is real, it exists, because God is real and made all things imbuing all things with His own goodness. There is no equal opposite to God, there are only creatures, creatures created as good, created by the good God, creatures made and imbued by God's own goodness. Thus evil cannot have its own objective existence, but is by necessity the absence, the rejection, and/or the twisting or malformation of the good. Evil, therefore is the estrangement from God, the rejection of the good, and in the case of us human beings, the denial of our own God-given humanity.
There is no cosmic evil; there are only creatures which are evil through their own willful rejection, denial, and removal of themselves from God and all goodness.
B) Is the devil a definitely existing being or a metaphor?
The devil is a creature, just like you or me. Christianity historically recognizes the existence of two kinds of rational creatures (in contrast to "irrational" creatures such as non-human animals, plants, and non-living things): human beings and angels.
The devil, aska Satan, is a creature of the second category, an angel. Specifically a fallen angel. Exactly how, when, why, (etc) of when the devil and the other fallen angels fell is unknown. The Bible doesn't seem particularly interested in providing that information, but merely assumes this to be the case.
C) What about demons, are they real?
Demons are just another word for fallen angels, they are also known as devils, plural. Where Satan is known as "the devil", all of the fallen angels are known variously as either devils or demons, these are synonymous terms.
The word "demon" is taken from the Greek word δαίμων (daemon) which has a complicated history. Originally, in Greek mythology and Hellenistic religion a daemon referred to an entire class of various divine powers, and is applied to a whole range of beings, even the Olympian gods are at times referred to as daemons, though most often daemons were more like sub-divine spirits: nymphs, satyrs, various nature spirits, weather spirits, even the souls of the dead were daemons. Daemons were neither inherently good nor inherently evil in Greek mythology, they were as diverse in their temperament, personalities, and dispositions as human beings.
Through the interactions between Jews and Greeks following the conquest of Alexander the Great, and all the complicated history that followed that, the word daemon came to be used by some Jews to refer to the fallen angels of Jewish literature and stories. While modern Judaism does not subscribe to the idea of fallen angels, Judaism in the 2nd Temple period was far more diverse, and there did exist a belief--at least with some Jews--in fallen angels, evil spirits. And so during the Hellenistic, and then later Roman occupations, the Greek word daemon became associated in Jewish thought with evil spirits, fallen angels, etc. And this is the theological landscape into which Christianity arose. And so Christians, likewise, used this word in the same sense. But where Judaism eventually ceased to have a belief in such things, it has persisted in Christianity.
The word "devil" likewise is of Greek origin, διάβολος (diabolos), a Greek word meaning "accuser". It is, in a pretty straight-forward way, a Greek translation of the Hebrew word shaytan (from which "Satan" is derived", which likewise means "accuser". In a broad sense it has been used, since antiquity among Christians as a synonym for demons, but in the specific sense it is used to refer to leader of the demons/devils, Satan, the accuser.
In the Middle Ages, in the West, the Latin translation of the Bible produced by St. Jerome dominated, in which we find a passage from the book of the Prophet Isaiah in which the king of Babylon is described with the satirical epithet "lucifer" (meaning "light-bearing"), the Latin translation of
heylel "shining", aka the planet Venus or "morning star". This is said of the king of Babylon satirically, mockingly, because the king saw himself as one of the gods in the heavens, like a shining light in the sky, but is brought low, has nothing, and shall weep as he is mocked by the nations. Medieval Christian exegetes saw in this mocking attack against the king of Babylon a kind of allusion to Satan and his fall, that the devil in his pride sought to lift himself up above the throne of God, but has fallen, lost, defeated, and will be the mockery of all time. And, as such, the word lucifer came to be seen as another name for the devil, which is why the devil/Satan is sometimes referred to as "Lucifer" as though it were a proper name.
Indeed, the devil is never given a name in the Bible, even allowing the exegesis of Isaiah to be an allusion to the devil, lucifer is still only an epithet. Likewise the devil, and Satan are simply descriptors, they are references to this creature as an evil accuser
D) Have you any testimony of encounters with or definite experience of A, B or C that you are willing to share?
Nothing definitive, or that I can't rule out as being entirely products of my own imagination. I am generally very skeptical of personal experiences--including my own.
E) How does having a world view that includes A, B, or C make a difference to how you relate to your understanding of how life/relationships unfold?
Generally, not much. I believe that the devil is defeated, Christ defeated him by dying and rising from the dead. The devil's chief works are that he is a deceiver and a liar.
Martin Luther suggested that the devil can be defeated by one little word--calling him a liar.
"
For all such books written against me, even if there were as many as thousands of them written every day and every hour, are very easily refuted with the single word, 'Devil, you lie,' just as that haughty beggar Dr. Luther sings so proudly and boldly in those words of his hymn, 'One little word shall fell him.'" - Martin Luther (yes, he does refer to himself in the third person in a self-deprecating way)
F) Thank you for answering my questions! ♥
Hope it helped somewhat.
-CryptoLutheran