I think you may have misunderstood me. By "nanosurgery" I meant not solely Drexlerian medical nanobots (though I wasn't ruling them out). Any drug whose design deliberately and intentionally causes specific, deliberate, and intentional changes to cell-level and molecular-level components of the human body, deliberately and consciously designed with a deep knowledge of the protein structures and cellular metabolic pathways involved, qualifies as nanosurgery, by my definition.
I contrast nanosurgery: deliberate, intentional action controlling the activity or structure of cellular-components - with medicine: the application of small molecules to the human metabolism to create a global, holistic effect with incomplete or nonexistent knowledge of the specific functional mechanisms. Surgery's salient characteristic is that it is intentional and deliberate manipulation to repair functionality. Medicine's salient characteristic is that it is a mapping of cause [primarily drug administration] to effect [changes in reported symptoms], with significantly reduced emphasis on the functional chain of causation between the two. As you said above, medicine is defined as "cheap tricks". That's what it does. That's what it's always been. When you're doing something intentional to a specific piece of a human to modify or repair it's functionality, that's surgery, whether it's done at the cellular or molecular level (nanosurgery) or at the macroscopic level (conventional surgery).
Prior to about 20 years ago, the vast majority of drugs were developed as medicine. Nowadays, more and more attempts at drug design are at least partially attempts to engineer tools for nanosurgery, per this definition. This is a good thing, and I see the trend continuing. If Drexlerian medical nanobots are possible at all, they would represent the logical endpoint of this trend, but I agree they represent an incredible engineering challenge and they may or may not end up being an economical technology for fixing broken human bodies.
The institution of medicine, defined as "understanding the human body well enough to, from basic principles, directly and intentionally repair diagnosed faults", only barely exists, and it is called surgery.
The historic division between medicine (as descended from folk remedies and alchemy) and surgery (as descended from the unsubtle craft of closing wounds and amputating limbs) is illustrative here. Medicine, by definition, is holistic. It descends from folk remedies, alchemy, and enchanted unguents. It has only recently and intermittently shown the slightest interest in drug mechanisms, and even that only to the extent that the analysis of drug mechanisms facilitates the development of new and profitable drugs. Medicine has never been about anything /but/ "adding small molecules to the oil", though it has been far more prestigious then surgery for about a century, since the late 19th century discoveries of narcotics, antibiotics, and vaccines. [Prior to this surgeons were considered far more reliable within their area of expertise, although neither had the degree of professionalization and societal status that they enjoy today.] You make the argument, and I'm inclined to agree, that medicine may very well be playing itself out - that the model that grabbed all the low hanging fruit there is more or less obsolete.
The future of medicine isn't medicine at all. It's nano-surgery. Though I suspect there will be a big turf war between medical professionals and surgical professionals as the medical professionals seek to redefine themselves as the ones implementing the procedures that actually work.
My take on the Doomsday Argument is that it boils down to the mundane and rather non-apocalyptic statement: "All other things being equal, I should expect to be born during a period in history when birthrates [of beings in my reference class] are high."
I can't quite see why this should imply anything at all about the shape of the population curve in the immediate future, let alone the long-term future.
"Lossless communication" doesn't quite seem to capture what is special about human communication. The difference is more about complexity of communication than losslessness. Being able to communicate using a fully recursive grammar is the key difference. I think that's the concept you're heading towards with "losslessness".
But which came first: being able to communicate using a fully recursive grammar, or participating in a viciously competitive political/social hierarchy and having the resulting selection pressure dramatically increase the size and complexity of our brains over what is, in geological terms, a ridiculously short period of time?
It occurs to me, reading your post, that I have almost no idea what people mean by "conscious system". I'm quite certain I am one, and I regularly experience other people apparently claiming to belong to that set too. I suspect that if we can nail down what it means to belong to the set of "conscious systems", we'll be much more readily able to determine if not being a member of that set disqualifies a thing from being an "observer".
Flying makes sense to me. The bottom 30k feet of the troposphere blocks a lot more potentially carcinogenic radiation than the aluminum skin of an airplane does, and the top 10% of all commercial flyers put in a /lot/ more hours in the stratosphere than the vast majority of the population.
A potentially-existent immortal mind that knows and understands you down to the microphysical level and loves you and appreciates being loved by you?
Except for the stipulation of a feminine gender, that is /exactly/ the mode of relationship Christians advocate developing, and claim to have developed with God.
In the WH40K universe, a small group of acquaintances, doing basic experimental research in applied parapsychology can, and eventually /will/ create a portal to Hell out of which pours a demonic army which then proceeds to do very unpleasant things to everybody on the planet. Given that the Imperium's standard policy in such an event is to sterilize the entire planet, total transparency as described above is probably a relatively stable, safe, and even pleasant model of society to live in (certainly relative to a lot of the other options).
These time preferences match mine.
This isn't about Jesus Christ, and it isn't about schizophrenia. It isn't even about religion. It's about the Simulation Argument.
If we have good reason to believe that we will be reliably simulated many times in the future, than we can trivially conclude that we are almost certainly inone of the simulations.