Don’t get me wrong. When we are studying ancient Greek culture, the plays are an important source. They can help us understand certain societal norms, social issues of the day, what was funny to them, and types of social relationships they thought were important.
But they need to be understood in context. They were never meant to be used as religious texts.
What I want to say next, Robert Parker (a frequently quoted scholar on this subject) said better, so I’m just going to let the man do his thing:
The noun miasma, ubiquitous in the tragedians, does not occur at all in Herodotus, Thucydides, or Xenophon. This might be taken to prove that the word’s stylistic level is too high, that the concerns of tragedy are unreal, or simply that tragedy and history treat different areas of experience. Modern social historians view such evidence with suspicion; court records, not extrapolations from Shakespeare, form the backbone of a classic modern study of English popular religion. Literary texts can only be safely exploited, it might be argued, to illustrate the existence and significance of which can be independently established.
— R. Parker, Miasma: Pollution and Purification in Early Greek Religion, 1996, p. 13, emphasis mine.
In other words, it’s Parker’s opinion that we should only consider fiction as a source to expound upon our understanding of something we know to be relevant outside of fiction.
If you think about it, this is common sense.
Like, don’t assume, from watching Buffy, that people in California believe that immortal vampires are real. Now, if, on the other hand, there are bunches of court trials about people who have broken anti-vampirism laws, and we have transcripts that read, “the defendant stated his age as 224, but couldn’t remember his exact birthday,” then, ok, see Buffy to get a lowdown on our vampire feels. It becomes evident as a part of our belief system at that point.
But wait, Parker’s got more for you, here, in his introduction:
Classical scholars, whose knowledge of subjects like pollution derives largely from their reading of tragedy, have tended to be less cautious, partly because alternative sources of information on these subjects are hard to find.
Parker’s tirade on this subject goes on for pages, and he goes on to say that a really eye-opening thing is to compare the comedies to the tragedies, and to bear in mind that they are products of the same culture.
The gods of tragedy are easily offended and without mercy once their ire has been attracted; those of comedy are good natured, forgive slights easily, and are just doing their best to keep a wayward humanity on track.
That is to say, theologies in these theatrical works were most likely constructed for dramatic effect.
So what’s a good source?
Hymns – These were created for, and often addressed to, the deities whom they are about. They are religious works and very likely to be representative of sincerely held religious beliefs. The Homeric and Orphic Hymns are examples.
Epics – Texts like the Iliad and Odyssey may be the closest thing in Hellenic writings to anything resembling a Bible. The large number of locales mentioned in the catalogue of ships (Iliad, Book II) is thought to exist as a way of including, by mention, all of the audiences for whom the story of the Trojan War was important, showing the breadth of the text’s importance. Alexander the Great slept with a copy of the Iliad under his pillow.
The two books, the Iliad and Odyssey, in tandem, give us the laws of hospitality, the exact way to make and cook sacrifices, the ways of necromancy and treating with the dead, the practices of courtship and marriage, and the exact shape of divine favor and fury.
Histories and Mythographies – Certain individuals made a living from collecting lore. They catalogued what people in various places thought happened there, in the past, as well as their beliefs and customs. There’s a bit of overlap between the two, of course, and modern historical methods didn’t exist then, so I’m grouping them together. Since these writers were interested in recording beliefs about both history and the gods, they are a mostly reliable source about what people from their own culture believed. Conversely, they are notoriously unreliable when reporting beliefs of those outside their culture. Herodotus, Thucydides, or Xenophon are all writers who focused on histories. Apollodorus (or Pseudo-Apollodorus) is someone to whom mythographies are attributed.
Legal Documents – We know that there was a real life Socrates, that Alcibiades was a naughty, naughty boy, and that a woman was once fined for riding a horse rather than walking in the processions during the Rites of Eleusis. We know these things because of legal records. Trial transcripts and steles containing the laws of the mysteries are both reliable sources.
In the same vein, ancient graffiti can tell us a lot about what was going on at the time, but be skeptical. It may be true that “Hermocrates was here” but we shouldn’t automatically believe that “all of the women love his cock.”
“But Thenea,” you might protest “these sources say almost nothing about actual miasma and its consequences.”
Yeah. It’s really hard to make claims about miasma (unless we are talking about the impurities generated by murder) if you stick to non-fiction sources from the ancient world. That’s basically what Parker, who wrote what is probably the definitive work on the subject, was saying. That’s why otherwise reputable historians, when they are writing about this subject, heavily rely on theatrical plays in a way that historians generally would not.
It is one thing to conjecture based on tragic plays and to argue that something was a concept, maybe, in a culture.
It is quite another to credulously apply what we read in an ancient tragic play to our modern theology and practice.
Katharmos, or purification, by contrast, is well attested in far better sources. We cannot assume that the question is “what are we being purified from, if not miasma?”
Not all cultures view purification as the removal of evil, or the removal of a metaphysical taint. There are other options. Perhaps it’s about separation between the ordinary and the sacred, or the separation between levels of sanctity, as it is in other nearby cultures. Perhaps it’s a token of respect, an acknowledgement of the importance of physical cleanliness. It is telling that purification before entering the temple is an always thing. So if you exit a temple, after being purified, and go back in, you need to be purified again. And, again, there are other regional cultures with similar constructs in their practice.
It is far more prudent to consider that we’re dealing with a Mediterranean culture, draw comparisons between well attested practices in other Mediterranean cultures, and pay attention to what is said about Katharmos in non-fiction sources.
There is no shortage of non-fiction written by and about ancient Hellenic culture. If, in all those thousands of pages, we don’t find very much written about miasma, we should take that into account when weighing the importance of this concept in modern practice.