What do pagans actually believe in? GK Chesterton's famous quote is frequently invoked: "When a man stops believing in God, he doesn't then believe in nothing – he believes anything." Unfortunately for easy analysis, the issue with pagans is more that they believe in lots of anythings, but what those anythings consist of is open to substantial debate.

I remarked in my previous article that currently pagans are realising that they don't really have much in common with one another. You'd think this would have been apparent from the get-go, and I'm sure in ancient times it was, but both wicca and, to a lesser extent, modern druidry, were set up in part as a reaction to prevailing Christianity and culture, and thus you have alliances that are somewhat artificial: more of a question of defining something by what it is not, rather than what it is. The demographic is changing these days, but a number of pagans came out of repressive Christian upbringings and fled as far as they could towards one of the principal opposites available to them.

Many pagans do believe in deities, or figures from mythology that are now treated as deities with little or no theological justification. The Welsh magician/trickster Gwydion is a case in point: mentioned in the Mabinogion, he's a dodgy anti-hero figure, now treated as a minor deity, whereas his rapist brother Gilfaethwy (happily) is not, and nor is his uncle the master magician Math. Why choose one and not the other? There's a randomness to the current Celtic pantheon, which is best explained by reference to cultural and literary factors – WB Yeats, we're looking at you – than to any theological underpinning.

Lacking much direct reference from the ancient Celts themselves – Roman reference to Celtic gods is patchy and many deities have dropped out of contemporary worship entirely – the history of current Celtic paganism emerges from the Celtic twilight of the late-19th century onwards. In wicca, the "goddess" Aradia stems from Charles Leland's 1899 novel, The Gospel of the Witches; whether Leland took her practices from old Tuscan folklore, or simply made much of it up, is in some question, but scholarly opinion tends towards the latter. Followers of Egyptian, classical or Norse pantheons are in a slightly more secure position as regards names and natures, but not necessarily where authentic practices of worship are concerned.

But it isn't necessary to worship any deity in order to be a pagan. It isn't really a set of theisms per se; rather, a way of interacting with the cosmos via a varied set of practices: following the ritual year, for example. We do count agnostics and atheists among our number, and there are a lot of people who regard deities as Jungian archetypes – facets of an entirely human psychology – rather than as anything real and "out there". There is debate about this, but it tends not to slide into anything recognisable as fundamentalism: we're not text-based; don't have a set dogma; and thus any argument is dependent on factors that are opinion-based and aesthetically or socially dictated.

What you don't tend to find in paganism are arguments as to whose god is more powerful – or more existent. Ontologically, the movements and organisations beneath this very broad banner are fluid and hyper-eclectic. You might be a follower of Horus, but that doesn't mean you're going to declare all-out war on worshippers of Baphomet. Nor do there tend to be the "angels on a pinhead" kind of disputes that arise between members of religions that have a text that is open to multiple interpretations.

This does not mean, of course, that we're an argument-free zone. Principal disagreements tend either to be much more petty (the precise timing of so-and-so's wiccan initiatory lineage, for instance); broadly political (no nice pagan likes a Nazi, and there are a handful of Aryan nation types in some traditions); or deriving from the assumption made by pretty much every practitioner of ceremonial magic that no one amongst one's peers knows what the hell they're talking about. And since pagan clergy tend to be self-appointed, or sanctioned through a usually short initiatory line, there's a dearth of authority to which appeal can be made. In many ways this makes the pagan traditions more transparent than other religions: with recent spiritualities, it's obviously easier to document their emergence and their history, plus the personalities that created them are known to a large number of individuals still living.

A friend of mine once asked a contemporary druid how one might become a druid. "You ask nicely," he replied, which more or less sums up entry into modern paganism.