The doctrine of a principle of evil supposes there to be a supernatural being that fell from heaven who tempts mankind in the earth and torments their wicked souls in hell -- theologically referred to as the devil and person-ologically referred to by the name Satan. The word Satan that appears in the English scriptures is an untranslated Hebrew verb meaning to "obstruct, oppose".  It is left untranslated and capitalized as a proper name solely based on the bias of the translators; the ancient Hebrew written language made no distinction between uppercase and lowercase letters.
Garden of Eden
It is commonly believed that the serpent in the Garden of Eden represents the devil in some way or another, however, the only way to come to that belief is through inferring it into the creation narrative.
“No Old Testament writer says, Moses by the serpent, Genesis 3, meant a fallen angel...”—Balfour, Walter, Three Inquiries p. 21
There exists no explicit declaration that the serpent is even an angelic being.
“Moses in no part of his writings, gives us any information about an angel who fell from heaven and had become a devil. Let any one read the five books of Moses, and he must be convinced that such a being is not once mentioned by him under any name.”—Balfour, Walter, Three Inquiries p. 21
The most that the serpent could have been was a very cunning animal.
“Now the serpent was more cunning than any beast of the field which the Lord God had made.”—Genesis 3:1 NKJV
No intimation is made that an evil being shape-shifted into a serpent or that the spirit of such a being inhabited a serpent. A stronger case can be made that the serpent was simply an animal that spoke in the same manner that a donkey did in Numbers 22:28.
However, if the serpent were a being of any kind it is strange that God never questioned it on account of its actions. Adam and Eve had to give an answer for what they had done, but the serpent never did. It is very possible that the serpent was not a being, but simply the personification of Eve's lust.
“But each man is tempted, when he is drawn away by his own lust, and enticed.”—James 1:14
One of the more credible places where it is supposed that proof of the existence of an evil being appears in is the book of Job. And even though it may speak in poetical language and begin on the premise that an evil being exists, it doesn't mean that one actually does exist, or that it is promoting such a notion.
“Now there was a day when the sons of God came to present themselves before the LORD, and Satan came also among them.”—Job 1:6 KJV
It is unclear whether the sons of God or the Adversary (also translated Satan) are angelic beings or men. There are many people who will contend one way or the other, however, all we can truly say for certain is,
“For as many as are led by the spirit of God, these are the sons of God.”—Romans 8:14 YLT
The notion of there being an evil being actually existing came from the ancient philosophers who assigned good effects to good causes and evil effects to evil causes; or good effects to a principle of good called God and evil effects to a principle of evil called the devil.
“Since nothing can come into being without a cause; and since that which is perfectly good cannot be the cause of evil, then there must exist a distinct principle in nature, as well for the production of evil as of that which is good.”—Balfour, Walter, Three Inquiries p. 186
“This belief in good and evil powers had its origin in the fact that man was surrounded by what he was pleased to call good and evil phenomena. Phenomena affecting man pleasantly were ascribed to good spirits, while those affecting him unpleasantly or injuriously, were ascribed to evil spirits. It being admitted that all phenomena were produced by spirits, the spirits were divided according to the phenomena, and the phenomena were good or bad as they affected man. Good spirits were supposed to be the authors of good phenomena, and evil spirits of the evil - so the idea of a devil has been as universal as the idea of a god.”—Ingersoll, Robert, The Gods and Other Lectures pp. 34-35
In the land of Uz, where Job was from, these where the philosophies of the day, but it wasn't the philosophy of Job who assigned the cause of all effects both good and evil to God.
“What, shall we receive good at the hand of God, and shall we not receive evil? In all this did not Job sin with his lips.”—Job 2:10 KJV
When speaking of his afflictions Job says,
“The LORD gave, and the LORD hath taken away; blessed be the name of the LORD.”—Job 1:21 KJV
And these concur with Isaiah 45:7,
“I form the light, and create darkness: I make peace, and create evil: I the LORD do all these things.”—Isaiah 45:7 KJV
It is clear that Job never thought that the source or the originator of the events that caused all his afflictions to be anybody other than God even though it is presupposed in the first two chapters of the book that an Adversary was.
“Indeed, we think it has been established, that the account of Satan in the first two chapters of Job, was introduced for the express purpose of refuting such opinions.”—Balfour, Walter, Three Inquiries p. 65
The only Adversary that actually existed was God. God acted as an adversary to Job in order that Job might be tested; in a similar way that God acted as an adversary (or Satan) to David (see 1 Chronicles 21:1 and 2 Samuel 24:1 KJV).
It is often inferred that the Lucifier named in Isaiah 14:12 is in fact Satan.
“How art thou fallen from heaven, O Lucifer, son of the morning! how art thou cut down to the ground, which didst weaken the nations!”—Isaiah 14:12 KJV
Below is commentary from Adam Clarke that provides reasonable exegesis regarding this passage.
“O Lucifer, son of the morning - The Versions in general agree in this translation, and render הילל (heilel) as signifying Lucifer, Φωσφωρος, the morning star, whether Jupiter or Venus; as these are both bringers of the morning light, or morning stars, annually in their turn. And although the context speaks explicitly concerning Nebuchadnezzar, yet this has been, I know not why, applied to the chief of the fallen angels, who is most incongruously denominated Lucifer, (the bringer of light!) an epithet as common to him as those of Satan and Devil. That the Holy Spirit by his prophets should call this arch-enemy of God and man the light-bringer, would be strange indeed. But the truth is, the text speaks nothing at all concerning Satan nor his fall, nor the occasion of that fall, which many divines have with great confidence deduced from this text. O how necessary it is to understand the literal meaning of Scripture, that preposterous comments may be prevented! Besides, I doubt much whether our translation be correct. הילל (heilel), which we translate Lucifer, comes from ילל (yalal), yell, howl, or shriek, and should be translated, "Howl, son of the morning;" and so the Syriac has understood it; and for this meaning Michaelis contends: see his reasons in Parkhurst, under הלל (halal).”—Adam Clarke Commentary on Isaiah 14:12
Isaiah 14 is a "parable against the king of Babylon"  yet no where does it explicitly say that it is referring to a supernatural being. In fact, more modern translations entirely do away with the name Lucifier altogether.
“How art thou fallen from heaven, O day-star, son of the morning! how art thou cut down to the ground, that didst lay low the nations!”—Isaiah 14:12 ASV
Furthermore, to say that the king or the kingdom of Babylon has "fallen from heaven" is to say that it has fallen from among the nations who had the most glory on the earth. No where in Isaiah 14 do the words Satan, devil, or angel occur -- those notions are all inferred into these passages.
The book of Revelations is thought to complete the story of Satan, fill in the missing pieces of the puzzle, and connecting the dots between the serpent and Satan.
“And the great dragon was cast out, that old serpent, called the Devil, and Satan, which deceiveth the whole world: he was cast out into the earth, and his angels were cast out with him.”—Revelations 12:9 KJV
If we take the verse above literally it is not difficult to see how such an interpretation could be made, but it is important to understand that that verse is not meant to be taken literally. In fact that verse and even the whole of Revelations is not a literal telling of past events, but a figurative foretelling of future events. The beginning of the book of Revelations confirms it,
“A revelation of Jesus Christ, that God gave to him, to shew to his servants what things it behoveth to come to pass quickly; and he did signify [it], having sent through his messenger to his servant John”—Revelations 1:1
Revelations is a sign, a prophecy, of things to come -- but the story of the devil is said to have already happened before the creation. References that are said to the chronicle the story of the devil in both Revelations and Isaiah are contained in prophecies. Yet prophecies foretell the future and the story of the devil is so far in the past that it is in the past before there was a past, it is said to be a creation before the creation, or a supernatural creation prior to all that is natural. The truth of the matter is that the great dragon, old serpent, and so called Devil and Satan mentioned in Revelations is simply the personification of evil not the story of a person or principle of evil.
The Tempter of Mankind
Satan is identified as the tempter in the Gospels  and it is thought that he first tempted Eve, even tempted Jesus, and now goes around tempting all of mankind. But how can a natural being such as man resist the temptations of a supernatural being? Man has no inherent power where by he can resist a supernatural being, yet he is commanded by God to resist it. Even if a man were to flee, he cannot outrun a spirit.
“If pure mother Eve could not resist such a temptation, how can it be expected her corrupt offsprings can resist any temptation?" ”—Balfour, Walter, Three Inquiries p. 26
Not only does Satan tempts every man, but he is said to be the source of all evil, even of the evil that exists in man. But if the devil is the cause of our evil thoughts and desires, then surely he must have the ability to inject that evil into our minds. Though it would seem strange that God would give such power to his adversary, over that of man, and yet unjustly require the consequence of the adversary's actions at the hand of man.
“God must be very merciful to the devil, to excuse him so long a time from eternal misery, yet send all the Sodomites there when he burnt up their city.”—Balfour, Walter, Three Inquiries p. 337
For the devil to be cause of every man's sin he must have a incredible power reviling that of God even the omnipresent ability to tempt multiple people simultaneously all around the globe. With all these powers the devil is supposed to have it is no wonder that,
“The devil, with many people, is much more feared than God.”—Balfour, Walter, Three Inquiries p. 191
According to the scriptures, it is always the lusts of men which cause them to sin and not the devil.
“Let no man say when he is tempted, I am tempted of God; for God cannot be tempted with evil, and he himself tempteth no man: but each man is tempted, when he is drawn away by his own lust, and enticed.”—James 1:13-14 ASV
James 1:13-14 above is the clearest passage concerning the subject: it does not use parables, or prophecies, or even personification.
“Besides, when the Scriptures trace crimes to their source in plain language, they never refer them to the devil, but to lust within men.”—Balfour, Walter, Three Inquiries p. 129
Over time the notion of an evil being lead some to believe that one actually existed and that belief changed the way they spoke about every source of evil, in that, everything became personified as the evil deity.
“Whatever is calculated to seduce men to sin, is represented by the sacred writers under the figure of a living agent, called the evil one-- the adversary--the enemy--the devil, and satan.”—Balfour, Walter, Three Inquiries p. 164
By implying that the evil cause for all our evil effects is a supernatural being of great evil, we shift the blame away from ourselves and toward something which we are powerless to stop and in affect become helpless.
“From our mother Eve to the present day, all men who listen to the lies of their own lusts, contrary to God's commandments, have found that the ways of transgressors are hard. ... But while lust is the true cause of all the mischief, an imaginery being has been invented and believed in, to bear the blame of it.”—Balfour, Walter, Three Inquiries p. 128-129
The theology that there exists a principle of evil named Satan warring against a principle of good called God is found in the far east religions even before the time of Christ.
“Some of the ancients, as the Persians, thought that there were two independent principles in nature, one the author of good, and the other of evil.”—Priestley, Joseph, Discourses relating to the evidences of revealed religion p. 191
“The Persians then had one good being or god, and also one evil being. Or, as Prideaux observes, "that is to say God and the devil." Christians in this are perfectly agreed with them, for they believe in one God and also one devil. Again; the Persians believed, that these two gods were the authors of all good and evil in the world. In this also Christians agree with them, for all good they ascribe to God, and impute all evil to Satan or the devil... But again, the Persians believed, that there was a continual opposition between their good god and evil god, and that this should continue to the end of the world. Then, the good god shall overcome the evil god, and thence-forward each of them shall have his world to himself, that is, the good god his world with all good men with him, and the evil god his world with all evil men with him. Christians contend, that there is a continual opposition between their God and the devil, and that this opposition shall continue to the end of the world. Then, God is to overcome the devil, and from that time hence-forward, God is to have his world and all good men with him, and the devil is to have his world, and all wicked men with him. Such are a few of the leading points of similarity between the ancient Magian faith and the faith of Christians in our day.”—Balfour, Walter, Three Inquiries p. 60
“Some of the Persians thought, that there were two gods, of different natures, the one good, called Horomazes, and the other evil, called Arimanius, the one resembling light, and the other darkness; and that in the medium between these was Mithras, who was therefore called the Mediator.”—Priestley, Joseph, Disquisitions relating to matter and spirit p. 317
And the Magian faith is the root of the Zoroastrian religion which was religion in Babylon which became Persia.
“The Jews were carried away to Babylon, and spent seventy years in captivity. Here, the Magian religion, revived and improved by Zoroaster, prevailed”—Balfour, Walter, Three Inquiries p. 66
In Babylon the Jews first learned and were lead to believe that there existed a god who was the source of all woes apart from God Almighty. And as can be seen in the New Testament, the Jews even after having returned to the land of Israel, still ascribed evil effects to an evil supernatural being which is translated as Satan.
“The fact is, the Jews knew nothing about the devil until they went to Babylon.”—Balfour, Walter, Three Inquiries p. 116
And while those beliefs may have existed at some point among the unlearned Jews, the belief in a devil is not part of the Jewish religion.
“In mainstream Judaism there is no concept of a devil like in mainstream Christianity or Islam. Texts make no direct link between the serpent that tempts Eve in the Garden of Eden from Genesis and references to a Satan in the first book of Chronicles and in Job. In Hebrew, the biblical word ha-satan (השָׂטָן) means "the adversary" or the obstacle, or even "the prosecutor" (recognizing that God is viewed as the ultimate Judge)”—Devil, Wikipedia
The belief in the existence of the power of the occult has become to be regarded as superstitious and Satan is part of that system.
“The horrors of witchcraft were all born of an ignorant belief in the existence of a totally depraved being superior to nature, acting in perfect independence of her laws; and all religious superstition has had for its basis a belief in at least two beings, one good and the other bad, both of whom could arbitrarily change the order of the universe.”—Ingersoll, Robert, The Gods and Other Lectures pp. 60-61
“But while people are generally agreed that witchcraft was all a piece of superstition and do justice to the devil in freeing him from all blame about it, yet they still continue to believe in his existence and extraordinary powers... Strange, beyond measure strange, that our fathers should so completely discard witchcraft as a superstition which the Jews imbibed from the Canaanites, where no devil was known, and yet continue to believe in the devil, a superstition which the Jews imbibed at Babylon many ages after.”—Balfour, Walter, Three Inquiries p. 179
“How is it possible that man should have any clear conceptions of natural truth, when his understanding is constantly insulted with a thousand incongruous and nonexistent relations, such as ghosts, witches, and devils, which perpetually disturb the imagination, and draw the rational faculties into the vortex of fancy and fanaticism?”—Palmer, Elihu, Principles of nature Gb. 206-207
“The characterization of an individual or/and group as an enemy is called demonization. The propagation of demonization is a major aspect of propaganda. An "enemy" may also be conceptual; used to describe impersonal phenomena such disease, and a host of other things. Throughout religious theology, "the Enemy" is typically reserved to represent the human tendency to do evil, often personified as a malicious deity, such as the devil or a demon.”—Wikipedia, Enemy
In the middle east, the United States is often seen as the Great Satan and the United States often sees every Arab as a demon or terrorist. Some of the enemies of the United States that have been demonized include Hitler, Castro, Chavez, Saddam Hussein, Ahmadinejad, etc. And the demon propaganda makes it that much more difficult to determine the truth concerning the actual character of these public individuals.
Most of the material and quotes in this article come from the book Three Inquiries by Walter Balfour. It gives a thorough presentation of the arguments against a fallen angel named Satan and completely explodes the popular superstition that Satan refers to an actual being.
- Wikipedia. Satan, Hebrew Bible
- Isaiah 14:4 ASV
- Wikipedia. Satan.
- Documentary, Iran is Not The Problem