Your points 2 and 4 above in that regard are not accurate. And Stipp's book reflects that.

No, they aren't, and no, it doesn't. I don't know how to be any more clear on that one.

He includes as examples Charles Brown-Sequard.

"In his extreme old age, he advocated the hypodermic injection of a fluid prepared from the testicles of guinea pigs and dogs, as a means of prolonging human life. It was known, among scientists, derisively, as the Brown-Séquard Elixir."

I find myself confused as to how anyone could legitimately, upon reading what you claim to have read, hold forth the stance you claim to hold. I find it to be internally and externally inconsistent with the axiomatic assumption of rational honesty.

In general maximal lifespans are roughly correlated with size in mammals. But, compared to most large mammals great apes have a larger lifespan even given good medical care to those species.

Average human lifespan (with medical care) is roughly analogous to the average human lifespan of the elephant, so that's not exceptional. But I didn't limit my statement to mammals but to endothermal.

Consider the possibility that we spend thirty years trying to throw all the spaghetti on the wall and none of it sticks It may be that I'm reflecting my own biases since I'm in a field (math) where lots of smart people can spend a lot of time working on a problem and it can still take hundreds of years to solve.

Attempts to project from the past into the future are doomed to failure when they do not take into account the present. When attempting to extrapolate and make predictions it is always a modal failure to use an incorrect model.

Medicine is not like math. It is far more like engineering.

I don't fully understand how your last paragraph is relevant to the bit it is responding to.

It was a selected example of the products of geriontology with regards to the behaviors of longevity in humans as they approach senescence. It was, therefore, a direct rebuttal of your hypothetical.

This is asinine. Science is a convergent, not a divergent, endeavor. Increased knowledge in one field necessarily alters or amplifies the impact of knowledge in another. I said nothing to contradict this and gave several examples of it being affirmed.

I don't understand what you mean by this, and all attempts to parse it don't seem to produce responses that make sense as a response to my remark. Can you rephrase or expand what you mean here?

... Increased knowledge in one field necessarily alters or amplifies the impact of knowledge in another. Are you familiar with the concept of scientific convergence?

This is a testable hypothesis and it has already been falsified. We share cellular metabolism with calorie unrestricted organisms, and not with CR-organisms.

The hypothesies has definitely not been falsified. There's evidence against it.

The hypothesis was "maybe humans already have calorie-restricted metabolisms". This has been falsified. This is not even remotely questionable. It's false. We've got proof on the matter.

We don't fully understand how reservatrol extends lifespan. We know that it has effects similar to caloric restriction, but without a better understanding of how it is doing that we don't know.

You're changing topics here. Resveratrol isn't the same topic as the hypothetical. How resveratrol works or doesn't work has absolutely nothing to do with the question of "do humans already have a calorie-restricted metabolic cycle?" -- saving that if resveratrol induces that cycle and we have no other proof on the matter, it would answer the question definitively negatively. Thankfully, we don't need to rely upon resveratrol to answer that question. It's already been answered.

Consider for example that we use a reservatrol-like compound for a while and then it turns out that something in the human diet that isn't in our lab environment interferes with it.

This is juvenile. There isn't a single thing on the planet that everyone consumes besides air and probably water. After that, it's isolation and elimination from diets. And that's how science is done. C'mon now -- let's try to restrict our hypotheticals to things that are at least remotely plausible within the current world-line?

The claim being made is weaker than I thought, although still a very strong claim.

It is a strong claim which emerges from a large series of independent small claims each with high probability individually. There is a saying; "three ifs ruin a plan". You'd have to have far more than three "ifs" for my claim to turn out to be wrong. Far, far more than.