Over the past eighteen months or so I've developed an interest in Satanism that has gone from ironic to not-serious-but-maybe-not-quite-ironic. This has become a perpetual source of questions as people try to figure out how serious I am about the whole thing, what does Satanism even mean, and so forth. The purpose of this piece of exposition will be to explain my interest and views on the matter.
A Brief Tour of Satanism
People who call themselves "Satanists" divide the term into two major groups. Theistic Satanists are people who actually believe in Satan as a divine being. I am personally a bit skeptical that there are really any true theistic Satanists of advanced age; to be a theistic Satanist would mean that you essentially believe in the Abrahamic concept of God and Satan and heaven and hell and all that, and yet you choose to embrace the path that will lead to eternal damnation and suffering. The other group is non-theistic Satanists, who don't actually believe in Satan as a divine being who is in opposition to the Abrahamic God, but do embrace some system of ethics or beliefs that is non-religious in nature but is somehow "Satanic". Most self-labelled Satanists are of the non-theistic variety, and the most prominent non-theistic Satanist movement is LaVeyan Satanism.
I think to understand the whole thing you need to start with the historical context for Satanism. Historically, the term has been levied at essentially any group of people or movement that is allegedly un-Christian in any way. For didactic purposes an interesting example here is the Leviathan cross, pictured below:
This symbol is commonly used as a "Satanic cross". Anton LaVey adopted it as a Satanic symbol associated with his Church of Satan, which he started in 1966.
The actual history of the Leviathan cross is rather interesting. It was one of the symbols used by the Knights Templar which was a Christian military order that existed in Western Europe about a thousand years ago. The Knights Templar were largely responsible for organizing and funding the first two Crusades. After the mid-12th century the fortunes of the Knights Templar started to turn, and the group fell out of favor with the Catholic Church and the various nation states of the day. The reason for their fall from favor is complicated but mostly has to do with political reasons based on military defeats in the Middle East, money owed to the Templars by various nations, and groups (such as the Catholic Church) who felt threatened by the power and influence of the Templars.
The church and various European governments started attacking the Templars and accused them of being a non-Christian organization and more specifially of charges such as heresy. Many of the Templars were tortured, forced to give false confessions, and burned at the stake. Later, after the rise of Freemasonry (another group that was attacked in much the same way) people tried to link the Freemasons to the Knights Templar as a way to discredit the Freemasons.
Thus the Leviathan cross is actually only Satanic in the sense that it's historically linked to a group that the Catholic church opposed. In fact the Knights Templar were more of a Christian fundamentalist group than anything else (which is why they started the Crusades in the first place) and any suggestion that they were practicing Satanism is absurd. The fact that today people recognize the symbol at all is largely due to Anton LaVey who claimed it as a Satanic symbol.
Likewise, many other aspects of "Satanic" imagery have very modern roots. The two other most prominent Satanic symbols are probably the inverted pentagram and the depiction/concept of Baphomet. Both of these symbols are due to a single person, the 19th-century French occultist Eliphas Levi. These are essentially products of Levi's imagination and were inventions for his treatises on magic. Other Satanic symbols that we recognize today were mostly inventions of 19th and 20th century occultists (e.g. Aleister Crowly and Anton LaVey) who were specifically looking to create Satanic symbols. Thus these Satanic symbols are mostly inventions of non-theistic Satanists who were specfically looking to create Satanic symbols.
In the modern era Satanic symbols and imagery are probably most associated with heavy metal music and most specifically with the black metal genre of music. Many bands within this genre incorporate Satanic concepts in their songs, album artwork, and sometimes performance costumes. Generally this is of a mostly fantastical nature. A very small number of bands associated with this movement---particularly in Norway---have actually expressed and acted in extremely misanthropic and anti-Christian ways. In particular, in the early 1990s there were church burnings in Norway infamously linked to black metal groups like Burzum. However, these incidents are extremely fringe, are hardly representative of the thousands of other bands associated with metal and black metal, and were mostly linked to the 1990s Norwegian black metal scene.
Satan in the Bible
Before proceeding, I want to briefly talk about what is actually said regarding Satan in the Old Testament and the New Testament.
In the Old Testament the story of Satan is described briefly in Isaiah 14:12-15 and Ezekiel 28:12-19. Satan is also mentioned in passing in a few other Old Testament books, notably including Job ch. 1-2 where God has a discourse with Satan about his devout subject Job. In Christian doctrine the serpent from Genesis who tempts Eve is commonly held to be an incarnation of Satan. It's worth noting that while this is Christian doctrine, the serpent is not actually identified as Satan in Genesis, so other Abrahamic religions (e.g. Judaism) do not necessarily agree on this point.
In the New Testament Satan also makes a few very brief appearances. Satan appears during the story of the temptation of Christ, which is told in the Gospels of Matthew, Mark, and Luke. The Book of Revelation makes numerous references to Satan in a propheptic and apocalyptic context.
All said, there's really not a lot of material on Satan in the Bible. If we go purely off the Biblical texts it would be rather hard to formulate a philosophy or religion around Satan, as there simply isn't enough material to really understand who Satan is or what he stands for (other than in a superficial manner). In fact, much of the popular Christian concept of Satan actually comes from later interpretations of Satan from non-monastic sources. For instance, the epic poem [Inferno](https://en.wikipedia.org/wiki/Inferno_(Dante)) from Dante's Divine Comedy provides much of the popular understanding of Satan, although this is purely a work of fiction. Similarly William Blake wrote a number of influential works such as The Marriage of Heaven and Hell that have influenced the popular conception of Satan---but these works are Blake's personal beliefs, and not religious texts.
So Like... What Does It All Mean?
To be clear: I don't consider myself to be a Satanist in any sense of the word. My so-called religious affiliation is atheism or perhaps more specifically secular humanism. That being said, by my own admission I have a lot of curiosity for Satanist aesthetics and I've accumulated a small collection of Satanist artwork, records, and even tattoos. The more I've dug into this movement the more I've found it intriguing and the more I've understood the reclaiming of Satanism.
With the historical context for Satan and Satanism in place, it should be clear that it's impossible to give a unified coherent explanation or study of Satanism, because one does not exist. Multiple independent groups of people have claimed or adopted Satanist imagery and symbolism. The concept of Satanists as devil worshippers is essentially a myth. Even if there are some bona fide theistic Satanists, the form of theistic Satanism they practice is a modern creation that has no real historical lineage.
Without question there are a small number of historical precedents for extremely anti-social groups or people who are linked to Satanism. However, it's also worth noting that there are a far greater number of anti-social groups and people linked with far-right interpretations of mainstream religions including Christianity, Judaism, and Islam.
The concept of Satanism as a movement that is anti-Christian or is somehow defined by an opposition to humanist or Christian ethics is fundamentally flawed. In fact, I think this viewpoint is largely one that has been created by Christians who assume to know what Satanism stands for without actually having researched the matter. If Christianity is right, then anti-Christianity must be wrong by definition, and therefore the view that Satanism is anti-Christian is an easy way to discredit the movement without a real attempt at critical analysis. My thesis then is that Satanism is a rejection of this---that is, a rejection of non-critical thinking. By adopting Satanist imagery or symbolism inviduals are automatically rejecting those who refuse to engage in rational and critical thought.