A 2024 paper with 81 coauthors presented different views of aging:

“This article highlights the lack of consensus among aging researchers on fundamental questions such as the definition, causes, and onset of aging as well as the nature of rejuvenation. Our survey revealed broad disagreement and no majority opinion on these issues.

We obtained 103 responses (∼20% of which were submitted anonymously). The respondents included 29.8% professors, 25% postdoctoral fellows, 22.1% graduate students, 13.5% industry professionals, and 9.6% representing other categories (a total of eight additional groups).

When does aging begin? At 20 years (22%), gastrulation (18%), conception (16.5%), gametogenesis (13%), 25 years (11%), birth (8%), 13 years (5%), and 9 years (4%). Nobody chose the only remaining option (30 years).

It is clear from responses that aging remains an unsolved problem in biology. While most scientists think they understand the nature of aging, apparently their understanding differs. Where some may stress the importance of targeting underlying mechanisms, others focus on ameliorating the phenotypes.”

https://academic.oup.com/pnasnexus/article/3/12/pgae499/7913315?login=false “Disagreement on foundational principles of biological aging”

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I’ll assert that these researchers were unable to incorporate information outside of their chosen paradigm. This would explain why only 18% understood the embryonic stage of gastrulation as aging’s start, although the 2022 paper Epigenetic profiling and incidence of disrupted development point to gastrulation as aging ground zero in Xenopus laevis provided epigenetic clock evidence that:

“It is not birth, marriage, or death, but gastrulation which is truly the most important time in your life.”

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I’ve cited Josh Mitteldorf’s work about aging a few times. His paradigm of aging is in his 2017 book Cracking the Aging Code: The New Science of Growing Old – And What It Means for Staying Young that:

“Aging has an evolutionary purpose: to stabilize populations and ecosystems.”

However, there isn’t evidence of such causal inheritance mechanisms that would begin an organism’s aging during embryogenesis, i.e., that an embryo’s development of aging elements at gastrulation is causally affected by population and ecosystem factors.

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Dr. Goodenowe recently had a casual conversation Episode 8 – Perpetual Health, Exploring The Science Behind Immortality where he asserted items such as:

“What we’re all fighting is entropy. Entropy is the tendency of all things to reach a level of randomness. Aging is not a disease. It’s just apathy and entropy. The body just doesn’t care – people don’t pay attention.

This notion that we are programmed for death is wrong. We’re not programmed to die. We actually teach ourselves to die. The body learns how to die, so as your function decreases, it adjusts. It appears to be programmed because of the association with chronological age.”

I haven’t seen any of his papers that put these and his other assertions up for review. For example, I doubt the entropy-caused randomness assertion would survive peer review per Stochastic methylation clocks?:

“Entropic theories of aging have never been coherent, but they are nevertheless experiencing a resurgence in recent years, primarily because neo-Darwinist theories of aging are all failing. I find this ironic, because the neo-Darwinist theories arose precisely because scientists realized that the Second Law of Thermodynamics does not apply to living systems.”

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The funny thing about failed aging paradigms is that quite a few of their treatments improve healthspan, but not lifespan. If they don’t “target aging underlying mechanisms” they “ameliorate aging phenotypes.” None so far have positively affected both human healthspan and lifespan.