Indeed, it seems he didn't read the source. French is studying researchers, not patients. His chapter surveys what theories were floating around (pun intended) at the time, and how they can be taxonomized and characterized. I'll explain it using a hypothetical example.
Let's say we have two people, Tom and Dick. Tom is an artist. Dick is a lawyer. One day, they both have a heart attack and, upon resuscitation, both claim they had a near-death experience. Among the observations each reports is what Greyson would descfribe as a "out-of-body experience." (French focuses on OBEs, but not to the exclusion of other NDE factors.)
We have three other people now: Harriet, Martha, and Joyce. Harriet is a spiritualist author who specializes in books on near-death experiences. Martha is a neurologist. Joyce is a research psychologist. Naturally each might want to interview both patents. When they do, both Tom and Dick say, "It seemed to me like I was floating above my body."
What French is trying to say is that the most likely explanation Harriet is going to come up with is that how the patients subjectively characterized their sensations was what objectively happened, as fact. "It seemed like you were floating above your body because part of you actually
was." Harriet's peers, as a matter of statistical survey, most prevalently propose some sort of literal separation of consciousness (French doesn't say soul) as the explanation for the feeling of being outside one's body. She represents one of the schools of though that French surveys.
Martha instead might say, "That's very interesting. We know that a person's sense of body location, surroundings, and equilibrium is controlled by a portion of the brain in the temporal-parietal region. When we stimulate this part of the brain and disrupt its normal function, the patent reports a feeling of being outside his body. I know that seems weird, but we have to remember that all the functions of the brain are going to be perceived as if they were sensory inputs. Now we probably won't be able to investigate the markers of such a causation in your particular cases because the cardiologist was more interested in saving your lives than in collecting data. This is why we prove the causation in the lab using controlled experiments and then generalize the results to situations in which the demonstrated causes might plausibly arise."
And Joyce might say, "We have seen that when people believe they are facing great danger, they sometimes dissociate their conscious thoughts from the surroundings. This might be perceived subjectively as not being inside your body. We think it's a way to shield the conscious mind from things that it doesn't want to deal with."
In summary, Harriet's theory is what the spiritualist school of thought most prevalently applies. Martha's is the most prevalent theory among the physicalist school of thought. And Joyce's is the most prevalent among the psychologist school. What's important to realize in French's study is that Harriet's conclusion has bugger all to do with what Tom and Dick each think.
Tom says, "I've always thought that my art came from somewhere deep inside me that wasn't really part of my physical manifestation. Harriet's interpretation speaks the most profoundly to me." Neither Joyce nor Martha need to revise their theories accordingly because neither of them is based on whether the patients themselves understand or accept the science.
And Dick might say, "I hear you, but I'm quite prepared to believe that the sensation was simply an illusion. Since my predetermination is to follow the evidence, I tend to prefer the explanation for which there is testable evidence, although I do also see some merit in the psychology theory too." Harriet need not change her mind. Her decision to take the out-of-body claim at face value was
hers; it had nothing to do with whether Tom or Dick agreed with her.
We have to endorse French's decision to taxonomize as he does because the rhetoric supporting the calculus of parsimony in each case has few if any common axioms. It's not as if Harriet just digs in her heels and sticks with her explanation because she's stubborn. The rhetoric proposes that the patient's perception to have been outside his body should be taken as if it were a literal observation because it's a
de minimis interpretation. All the others, they say, require additional factors which lack evidence. But that calculus arrives at parsimony only by ignoring that the existence of the soul is assumed. You can do that in spiritualist circles, and if one presupposes the existence of a soul then the take-at-face-value interpretation comes across as parsimonious. Circular, if OBE is to be considered proof of the soul, but not without intellectual appeal.
What's important to realize is that Tom and Dick don't appear anywhere in French's research. He's twice removed from any information regarding whether the patients themselves interpreted their perceptions as literal records of fact, if any such information was even collected at all by actual investigators. He studies only the Harriets, Marthas, and Joyces.