No, this is not about equivalent series resistance. It's not even about erythrocyte sedimentation rate. The ESR of the title is Eric S. Raymond. (For those of you who don't know who ESR is, he's one of the central semi-mythic figures of hackerdom. He was instrumental in forming the `open source' concept and movement. He formulated the cathedral-vs-bazaar models of open-source development. He maintains the Jargon File. And he wrote many other things besides. Not everyone in hackerdom likes him. Not everyone agrees with him. But I think there is general agreement that he is an important figure.)
He wrote a piece called Dancing With The Gods, which, at least as of this writing, is available here. It's an interesting read, but I think he rather misses some points.
His view of the Deities is an interesting one, but he appears to fall into the trap of thinking it is objectively correct. I believe there is no such thing as an objectively correct view of the Divine. I'm not sure that even the existence of the Divine is a question which has an objectively correct answer.
He does write, though, that "[m]agic is loose in the world", but that it "is not the magic of fantasy — no would-be violators of the laws of physics need apply". The part after the dash, I agree with, but I don't interpret it the way he does (which I suspect is the way most people would interpret it), and I disagree with his interpretation. (It's certainly conceivable he agrees with my interpretation, as sketched below, but the `not the magic of fantasy' line makes me doubt it.)
Magic is indeed loose in the world, and it is no violation of `the laws of physics'. But it is the magic of fantasy, just toned down in most cases. I take this stance because I see `physics' as a description of our world, and its laws are what our world runs by, so by definition everything that happens conforms to them. But I have seen too much magic happen to deny it. What I disgaree with is the notion that the actual laws of physics, the laws our reality runs on, are exactly and only the ones taught in physics departments. ESR appears to fall into the trap of believing that we (for whatever value of `we') know all the laws our reality runs by. We (where, again, `we' is a fuzzy term) are constantly refining those, and one major lacuna in them at present is their lack of any description of magic. I speculate that this is because they also take no account of consciousness or will; they restrict themselves to observer-independent phenomena which are repeatable on demand in the presence of more-or-less arbitrary observers. Those stances more or less guarantee that they will completely fail to handle magic. (They also fail to handle various other things, notably the `soft' sciences such as psychology, as a result. But those are too widespread even now to be denied effectively.)
Admittedly, `magic' is a fuzzy term. I have been trying to come up with a good definition of it, on and off, for months if not years now, so far with a notable lack of success. Perhaps the most popular definition I've seen is that magic is the production of changes in one's environment in accordance with one's will. But this is both too inclusive and too exclusive. Too inclusive, in that if (say) I want a pencil on my desk to be somewhere else, I can pick it up and put it there: I have caused a change in my environment in accordance with my will. But if that falls under the `magic' rubric, it becomes so diluted and inclusive as to be effectively meaningless and useless. And too exclusive, in that many people, including me, think that some of the deepest and most important magic is to effect changes in oneself, not in the environment, and to exclude that from `magic' is to do a disservice to both the reference and its referent. (And, just to confound matters, I'm not convinced that the interface between consciousness and the human body that allowed my will to (putatively) cause my body to pick up that pencil and move it is fundamentally different from the stuff generally considered `magic'.)
I don't know whether the `missing' laws are amenable to an easy mathematical formulation. ESR wrote a different piece, at least somewhat relevant to that, too; it's here. But it does occur to me that there is no a priori reason why those laws must be amenable to any formalization; it could, for all I know, be that it is an essential attribute of magic that its underlying laws not be comprehensible to us. As I have occasionally remarked, one of the most inexplicable things about our universe is that it is explicable.
Most of the magic I've seen is, yes, healing and divination. But ESR misses the point when he writes that "human minds have more control over their bodies than we normally think"; indeed, the notion of a human mind is one that physics, in the "what is taught by physics departments" form, has no room for. In my experience, that community considers the mind to be just patterns of activity in the brain, largely because it refuses to admit of anything else the mind could be, and it has no description of will or explanation of how it can influence any body. I was once shoulder-tapped by my Powers for the sake of someone halfway across the city, whom I had no mundane way to know/perceive anything about. And I knew someone whom the Canadian National Institute for the Blind had examined and certified she had no optic nerve function whatsoever, but I've played cards with her, using my own cards, so it's clear she has something functionally equivalent to sight when she wants to. Her reported perception of it is entirely magical and I see no reason to think she is either lying or mistaken.
There was a Mythbusters episode that hooked a plant up to a very sensitive meter (voltage or resistance, I forget which) and discovered that Grant could influence it from the other side of the room, across a wall. This disturbed them; they switched to a different kind of meter and spent the rest of the episode demonstrating that that meter showed no such effects in numerous situations. I have seen it said that true scientific discovery is not "Eureka!" but "Hmm, that's funny...". They failed spectacularly at that. (To be fair, they are entertainers, not scientists. But in that respect I don't see them as differing much from the scientific establishment.)
The medical branch of the scientific establishment even acknowledges the effect that the mind can have on the body, a form of what I would call healing magic. Even untrained, this is so strong that it has to be compensated for in drug tests, where it is called "placebo effect" and is another case of ignoring "hmm, that's funny...". (This failure to investigate seems mysterious until you realize how heavily invested the medical establishment is in its stance that magical healing is nonexistent.)
So, I think the major mistake ESR makes is believing that the current physics establishment's `laws of physics' is a complete description of our reality. It never has been in the past, I see no reason to think it is now, and I see enough magic happening that I consider myself to not only see no reason to think it is complete but to see reason to think it's not complete. There are laws our reality runs on, presumably, but those laws involve, call for, support, describe, whatever word you want, more than the physics establishment's laws cover. And those differences, those gaps, are, to put it loosely, where magic comes in.