See this passage, which refers to Carmen’s doctor as “Dr. F.”:
In any case, the question of absolute “proof” is of no interest to me. We are in no position to wait for absolute anything. We need help now. And incontrovertibly, there is evidence — not proof, but real evidence, published in a score of leading academic journals — that animal fat makes MS patients worse. It is very clearly something to avoid. In my view, which is the view of a highly motivated layperson whose livelihood is, coincidentally, based in doing careful research, there is not the remotest question that impaired lipid metabolism plays a significant role in the progression of MS. Nobody understands exactly how it works, just yet, but if I were a neurologist myself, I would certainly be telling my patients, listen, you! — just in case, now. Please stick to a vegan plus fish diet, given that the cost-benefit ratio is so incredibly lopsided in your favor. There’s no risk to you. The potential benefit is that you stay well.
But Dr. F, who is a scientist, and moreover one charged with looking after people with MS, is advising not only against dieting, but is literally telling someone (Carmen!) who has MS, yes, if you like butter, you should “enjoy” it, even though there is real live evidence that it might permanently harm you, but not proof, you know.
In this way, Dr. F. illustrates exactly what has gone wrong with so much of American medicine, and indeed with American society in general. I know that sounds ridiculous, like hyperbole, but I mean it quite literally. Dr. F. made no attempt to learn about or explain how, if saturated fat is not harmful, Swank, and now Jelinek, could have arrived at their conclusions, though she cannot prove that saturated fat isn’t harmful to someone with MS. The deficiency in Dr. F.’s reasoning is not scientific: it’s more like a rhetorical deficiency, of trading a degraded notion of “proof” for meaning, with potentially catastrophic results. Dr. F. may be a good scientist, but she is a terrible logician.
I might say, rather than “terrible logician,” Dr. F. is someone who is a poor reasoner — who has made herself a poor reasoner by dividing the world into things that are proven and all other things, and then assuming that there’s no way to distinguish among all those “other things.”
You can see how this happens: the field of medicine is moving so quickly, with new papers coming out every day (and being retracted every other day), that Dr. F. is just doing intellectual triage. The firehose of information becomes manageable if you just stick to things that are proven. But as Bustillos says, people like Carmen don't have that luxury.
What an odd situation. We have never had such powerful medicine; and yet it has never been more necessary for sick people to learn to manage their own treatment.