The difference between satire and sarcasm is the difference between surgery and butchery.
— Edward Nichols
Ask any ten people what the difference between sarcasm and satire is and you'll probably find that only one or two can correctly delineate the difference. There may be many reasons why that's true, but I suspect the main one will be the perception we have of the intended sarcastic or satirical comment or vehicle for said sarcasm or satire.
When we agree with the sentiment that is being expressed, we're inclined to define it as satire, when we disagree we label it sarcasm. The reason I bring this up is that a friend was relating something he had heard on the radio that he didn't like and he called it sarcasm. When he related the exchange in question, it was immediately clear to me that it had been meant as a satire.
This is, and always has been the difficulty with edgy humor. Throw irony into the mix and it becomes all the more fraught with peril. Not so, however with parody. Parody is almost always understood immediately, even when the observer doesn't care for a parody of the subject. That, I suspect is because parody is a gentle form of humor that isn't intended to demean the object in any way. Therefore, parody is safe and mostly approved of. Parody takes an established work, be it a piece of writing, a song or a movie and pokes fun at the subject matter without making any judgement call on it. The songs of Weird Al Yankovich are a prime exampe. The downside of parody is that it tends to fade away with time. It has no real substance and therefore doesn't linger in the mind.
Satire, on the other hand, is parody with an edge. Its purpose is to expose flaws in its target and point them out with humor, often incorporating irony as well. A modern day example is South Park. A very satirical show that also uses irony and sarcasm to drive home its point, and that second aspect is the likely reason many people are put off by it. Well-honed satire that doesn't rely on sarcasm is usually better received.
Sarcasm has only one intent, and that is to wound its target. The shortcoming of sarcasm is that even if those who hear it agree with the sentiment being expressed they may be inclined to have an unfavorable view of source of the sarcasm simply because it is so negative. When sarcasm is employed it rarely has any other point to make than that the target is worthy of contempt. For this reason, the quote at the beginning of this piece is correct, sarcasm is butchery. It has no intention of pointing out why it's target is worthy of contempt or what might be done to improve it, it merely sets out to wound whatever it finds to be beneath contempt.
So then, clearly satire is the surgery to sarcasm's butchery. It's intent is to demean it's target, but with the intention of pointing out why it deserves derision and usually it seeks to point the way to a better situation. Irony is often the tool used to point out how and why the target is wrong. Irony, however, is yet another term many people understand only vaguely.
If you ask a person in an offhand manner to define irony, most will struggle to do so. Most people know irony when the see or hear it, but it's exact definition will elude them. For the record, irony is what occurs when the outcome of a situation is the exact opposite of what was intended. That is why it's so useful in satire.
To sum it all up, parody is gentle fun that has little or no substance; it's fun, but ultimately toothless. Satire is parody with fangs, it seeks to persuade that a situation or individual is wrong and in need of change, but it does so with intelligence and wit. Sarcasm is naked aggression with no intent of redemption for its target, and therefore often defeats it's own purpose by creating sympathy for it's target. Irony is the spice that can be added to any of the above, but shines most especially when used as an adjunct to satire.
