For such a small country, Jamaica's culture has an amazing global reach. Everywhere I travel—Haiti, New Caledonia, New York, Lisbon—I stumble across Rastafarian music, colours, and the infamous marijuana leaf printed onto clothing.
But I have often wondered why Rastafarian gear is sold alongside bongs, but never in religious shops. After all, smoking pot and growing dreadlocks aren't just youth culture; they're expressions of a religion.
If you listen to the lyrics of Bob Marley's songs, most of what he writes about is finding God and freeing black people from oppression. It is no accident that these two themes sit side-by-side: Rastafarianism as a religion developed as the black man's re-reading of the white man's bible.
It all started under colonial rule. British missionaries introduced Christianity to Jamaica very early on, when there was still slavery in Jamaica. Slaves were attracted to the churches because the missionaries not only converted them; they provided them with an education, and often also advocated against the worst practices of slavery. Slaves saw in Christianity a way to escape from the suffering and subordination that they experienced on the plantations.
Smoking pot and reading the bible go hand in hand. In fact, Rastafarians suspect that smoking pot is illegal because it reveals the truth.
However, when Jamaica's slaves were emancipated in 1838, they quickly learned that equality was not going to be granted to them. They became disillusioned with the promises of their rulers, even seeing the bible as "a white man's trick" that Europeans had re-written to their own advantage.
In fact, Christian use of European-centric imagery, such as paintings of an improbably white-skinned Jesus, confirmed their suspicions that white men were twisting God's word. They came to the conclusion that the bible was actually written by black people, for black people, but that it would have to be re-interpreted to find its original meanings.
So, some Jamaicans set about read themselves back into its story. Smoking marijuana during bible discussion sessions (called "reasonings") is considered crucial to free one's mind and discover the "true" meanings hidden in the text.
Rastas claim that this is exactly what the bible tells them to do in passages such as "Jah causeth the grass to grow for the cattle, and herb for the service of man" (Psalm 104:14), and "Behold I have given you every green herb bearing seed" (Genesis I:29-30).
Smoking pot and reading the bible go hand in hand. In fact, Rastafarians suspect that smoking pot is illegal because it reveals the truth. 
How does all this make Rastafarianism fundamentalist? Fundamentalism is essentially the strict adherence to a text and its laws. This would seem to disqualify Rastafarianism, given that it has reinterpreted the bible so radically. However, one only has to see how many different interpretations of the bible there are among Christians to realise that all texts are read subjectively.
The proof of fundamentalism is not so much whether a text is being interpreted literally, but rather how much importance that one text has in a religion (many religions use multiple texts). Given that Rastafarianism puts a lot of emphasis on the bible as the source of truth, it is technically fundamentalist.
Why, then, is Rastafarianism so popular? It is not only that Bob Marley was a great musician, or that the rebellious aspects of Rasta appealed to youth globally, although these were certainly crucial elements fuelling its global spread.
Rather, the messages in the songs—unity, love, redemption, freedom from oppression—struck a chord with many people, especially in colonial and ex-colonial societies. Some took on the spiritual message; others dug the liberation. Due to the rebellious nature of the religion, many elements were readily incorporated into a global youth culture.
The only place where Rastafarianism doesn't seem to have any influence is in other religions. Given its radicalism, this is not surprising. While one could argue that smoking pot in the name of Jah isn't actually that different to drinking wine for Jesus, Rastafarianism's reinterpretations went a little to far for contemporary Christianity.
After all, fundamentalisms are normally concerned with maintaining continuity with the past, not with rewriting the religious history books altogether.