Critique of the non programmed aging rationale

CRITIQUE OF THE NON-PROGRAMMED AGING RATIONALE

“The alternative to thinking in evolutionary terms is not to think at all.”

Peter Medawar

From the dawn of human civilization, the aging paradigm has been the central conceptual framework for perhaps the most significant field of the life sciences. Young people are healthy and strong; older people suffer from progressive deterioration of strength, vitality and health. The infirmities of aging are inevitable and irreversible, and the biological changes that we experience with advancing chronological age are an integral part of a genetically mandated aging process that ultimately results in death.

In all realms of scientific knowledge, the aging paradigm is unique. It has never been questioned or tested scientifically. No theory successfully explains what aging is or how or why it happens. It is a set of preconceptions based solely on subjective perceptions. Everyone gets old, becomes infirm and dies, so aging is assumed to be a monolithic, inevitable, irreversible and genetically inherited trait.

But the study of aging is a natural science. A primary purpose of the natural sciences is to distinguish objective reality from subjective perception. Unless the preconceptions that we form from our observations can be substantiated by a theoretical framework that explains why those observations reflect reality, the model resulting from those observations cannot be accepted as reality.

This essay will focus on the Non-Programmed Aging (NPA) rationale. Prior to the the work of the Institute, no one has ever questioned the assumption that FDS is a genetically inherited trait. The debate has always been between the two rationales that attempt to explain how a trait that is so clearly detrimental to the individual organism is even possible given the principles of natural selection. Since Darwin proffered only two possible rationales, NPA proponents assume that all they have to do in order to prove their case is to conclusively prove that there is no pro-active physiological mechanism that causes aging in most species.¹ As Sherlock Holmes once said, “When you have eliminated the impossible, whatever remains, however improbable, must be the truth.”

As noted in the essay entitled “Critique of the Programmed Aging Rationale,” PA adherents have never produced any convincing evidence of the existence of their purported pro-active aging mechanism. Nor have they advanced a theoretical framework that explains why all organisms necessarily would have inherited that physiological mechanism. At best, they have suggested a rationale for how such a mechanism could be consistent with evolutionary principles. And NPA advocates have put forth a number of excellent arguments that demonstrate other flaws in the PA position. However, the PA advocates have a compelling argument why the evolutionary neglect view championed by the NPA camp is also fatally defective. How could evolution simply ignore the accumulation of damage in humans that results in diminution of functionality as early as the third decade of life?

By emphasizing the importance of the human maintenance system, the New Paradigm bolsters this argument. Intrinsic damage has afflicted every complex organism that has ever existed. For evolution to have designed humans without taking intrinsic damage into account would be akin to designing an airplane without taking gravity into account. Thus goes the PA argument, the failure of evolution to endow humans with an effective maintenance system proves that there must be some evolutionary benefit to biological aging. The Institute agrees with the NPA proponents that humans do not have a programmed aging mechanism. But it also agrees with the PA proponents that natural selection could not and did not overlook intrinsic damage.

Intrinsic damage is an inexorable force that afflicts all organisms. Principles of natural selection predict that each species would be endowed with a maintenance system that would counteract that inexorable force. However, because natural selection must make cost/benefit choices, the principles of natural selection predict that the maintenance system of any species will have a chronological limitation — it will remain effective only throughout the natural lifespan of that species. As explained in the essay entitled “Aging in Other Species,” that prediction is completely consistent with empirical data. Since both the PA paradigm and the NPA paradigm appear to be fatally defective, the New Paradigm embraces the third alternative. Rather than being an aspect of a natural monolithic aging process, FDS is itself a degenerative disorder that results from an environmental factor disrupting the intended operation of the maintenance system.

Since the New Paradigm concurs with the NPA paradigm with respect to its primary tenet (i.e., in most species, there is no physiological aging mechanism per se), this essay will focus on the key difference between the New Paradigm and the NPA point of view. A primary focus of the New Paradigm is the significance of the human maintenance system. A core preconception of the NPA paradigm is that human maintenance processes, if such processes even exist, are irrelevant to the discussion.

How NPA Views the Human Maintenance System

Since substantially all humans are afflicted with FDS, which progressively worsens until they die, a fundamental assumption of the aging paradigm is that humans are not endowed with effective maintenance systems. Because that preconception is taken as a given in the debate between the PA and NPA camps, NPA proponents have never tried to examine the actual human maintenance system. Commentators typically either assume that the inadequacy of the human maintenance system is a given, or ignore the role of the maintenance system altogether.

One reason that NPA proponents shy away from the maintenance system itself is that the acknowledgement that there are biological structures, such as the endocrine system, that are heavily involved in the operation of the maintenance system, exposes a fatal weakness in the NPA paradigm. Biological structures mutate. So long as there is any evolutionary benefit to be gained, a mutation that would allow the maintenance process to ward off FDS for a longer period of time (i.e., past the age of 20) would be favored by natural selection. So the only way to rationalize the preconception that the human maintenance system is incapable of preventing FDS in humans once they have entered their third decade of life would be to argue that either there is no evolutionary benefit to delaying the onset of FDS; or delaying the onset of FDS is simply impossible.

In Darwin’s time, human aging was assumed to be quite similar to animal NPD. Aging was something that happened to old people. It’s not that big a stretch for Darwin to have assumed that at some point very late in life, as is the case with NPD in other mammals, the human maintenance system loses effectiveness. However, now that science has established that symptoms of FDS appear in a typical contemporary human by the early 20s, proponents of the NPA paradigm typically tie the commencement of aging to “reproductive maturity.” Per the evolutionary neglect hypothesis, once one has reached the age where offspring are possible, evolution no longer cares about the subject.

That’s a significant contortion of evolutionary theory. A basic principle of natural selection is differential reproductive success, which boils down to selecting traits that maximize the number of offspring. It’s difficult to imagine a trait that is more directly related to reproductive success than a maintenance process that effectively delays the onset of FDS, thus extending the period of time that the reproductive system can function at an optimal level. But the NPA proponents would have us believe that once an individual has had the opportunity to produce a single offspring, evolution no longer cares. The NPA rationale would be somewhat plausible if it tied the commencement of biological aging/FDS to some theoretical point in time where reproduction is no longer possible. But to suggest that there is no evolutionary benefit to having the human reproductive system continue to function at an optimal level past the age of 20 is a bridge too far.

That leaves NPA proponents with the argument that an effective maintenance system is simply impossible. As is the case with many issues that relate to the aging paradigm, much of the discussion is based on preconceptions and hidden assumptions rather than explicit argument. For example, although NPA proponents deny the existence of any aging mechanism per se, they nonetheless unquestioningly accept the aging paradigm’s preconception that all physiological changes that are statistically associated with increasing chronological age constitute a single monolithic trait, with that trait being a process that is designed to result in death. The resulting hidden preconception is that the sole purpose of the maintenance system is to prevent organisms from dying. If an effective maintenance system is defined to be one that makes organisms immortal, then an effective maintenance system would of course be impossible.

A second approach utilized by NPA proponents is to identify certain types of damage that appear to be unpreventable. Two well-known examples are the mitochondrial free radical theory of aging and telomere attrition. Under these damage-based theories, the presumed purpose of the maintenance system is to prevent intrinsic damage. Under this view, since these (and many other) sources of intrinsic damage are inexorable forces, an effective maintenance system would be impossible.

The final approach is based on empirical evidence. Based on what we see every day, “everyone knows” that aging is inevitable and natural. Under this approach, the presumed purpose of the maintenance system is to prevent aging. The fact that everyone obviously ages proves that an effective maintenance system is impossible.

Each of the foregoing arguments to the effect that an effective maintenance system is impossible is addressed below.

Isolating FDS

One of the fundamental preconceptions of the aging paradigm is that all of the physiological changes that are statistically associated with increasing chronological age constitute a single monolithic trait – the “aging process”. The term “process” implies a coordinated series of steps designed to achieve a particular end. The presumed end to be achieved by the aging process is, of course, death. Thus the presumed purpose of the maintenance system is to prevent organisms from dying. Under this logic, the fact that all organisms eventually die proves that an effective maintenance system is impossible.

It’s remarkable that NPA proponents, whose core belief is that there is no aging mechanism, still adhere to the aging paradigm’s preconception that FDS is inextricably linked to dying. That adherence is evidenced by the fact that NPA advocates accept the aging paradigm’s norm that longevity is the preferred metric when addressing any issue relating to physiological changes that are associated with advancing chronological age. To anyone who is not blinded by the aging paradigm, the assumption that delaying the time of one’s death will necessarily delay the onset of FDS is the quintessential example of the logical fallacy of reversing cause and effect. Causation works in only one direction. Uncorrected FDS will result in death, and acute FDS has been the cause of substantially all deaths that are attributed to natural causes or old age. Thus, it is accurate to assert that one cannot substantially extend longevity without addressing FDS. But to assert that an evolutionary imperative that all organisms die is the reason for FDS is nothing more than the discredited PA argument that a causal factor (FDS) is caused by its ultimate effect (death).

The reason for the misconception that FDS is inextricably linked to death is that since science has not yet acknowledged that FDS is a disorder, it has never attempted to develop a remedy. So the symptoms of FDS inevitably continue to worsen until the subject dies. But that is true of all degenerative disorders. Degenerative disorders result from a disruption of the maintenance system. If the cause of the disruption is not corrected, the patient’s symptoms will progressively worsen until the subject dies. But that is the only correlation between FDS and dying. Assuming that FDS cannot or should not be isolated from a nonexistent aging process is no different than assuming that scurvy or any other degenerative disorder cannot or should not be viewed as a phenomenon separate from advancing chronological age.

Effective Maintenance Systems are Possible

Another variation on the impossibility argument is the assertion that maintenance processes can’t be completely effective because no biological process can be perfect.² It is true that no single maintenance process is perfect. But evolution has taken this into account. The human maintenance system includes backup maintenance processes that function at all levels of biological organization.

An effective maintenance system is one that prevents diminutions in functionality. The principles of natural selection predict that each mammalian species is endowed with a maintenance system that remains completely effective during the natural lifespan of that species. As discussed in the essay entitled “Aging in Other Species,” when limited to the evolutionary environment (where robust predator populations limit the natural lifespans of all species) that prediction is correct. If all mammalian species have maintenance systems that are 100% effective in the evolutionary environment, it’s difficult to accept the argument the it is impossible for humans to have a maintenance system that is effective past the age of 20.

Empirical Evidence

The preconception that humans are not genetically endowed with an effective maintenance system is not supported by any scientific theory. In fact, the preconception directly contradicts basic principles of natural selection. Nonetheless, per the aging paradigm, the fact that everyone appears to suffer from FDS is sufficient to establish that effective maintenance systems are impossible.

Before addressing the question of whether the purported empirical data is accurate, it is important to define the actual issue. The issue is one of impossibility. Are the NPA proponents correct when they assert that it is impossible for the human maintenance system to ward off FDS beyond the age of 20?

Suppose that we had never seen a 30-year old human who was not yet experiencing any of the symptoms of FDS. If that were the case, then the conclusion that it is impossible for the maintenance system to ward off FDS beyond the age of 20 would be an example of the black swan fallacy. The black swan fallacy is the conclusion that if X has never been observed, then X is impossible. Of course, we have all seen much older persons who show no signs of any functional impairment, so the black swan fallacy doesn’t really apply. NPA proponents would have us believe that X is impossible because X is only observed on rare occasions.

A related flaw in the preconception that the prevalence of FDS proves that effective maintenance systems are impossible is that the conclusion relies on the assumption that phenotype always matches genetic potential. The Institute uses the term “genetic potential” rather than genotype to highlight another misconception of the aging paradigm. The aging paradigm assumes phenotype is strictly determined by genotype, and that variances from genotype are rare and minor exceptions. In fact, the typical human never reaches her genetic potential at any point in her lifetime. The deviation between phenotype and genetic potential is typically quite large, and increases as the symptoms of FDS worsen over time.

By way of example, consider the fact that most of us have never seen a chicken fly. One could conclude that because the phenomenon had never been observed, it is impossible, as a matter of genetic potential, for a chicken to fly. That conclusion is invalid as a logical matter because it is an example of the black swan fallacy. It also turns out to be incorrect as an empirical matter, because, from time to time, a farmer will observe the consequences of a chicken having flown. The reason that chickens do not appear to have the ability to fly is because of environmental factors.

The chicken example also illustrates the distinction between genetic potential and phenotype (what we actually turn out to be). No one questions the fact that one chicken showing the ability to fly proves that all chickens have that genetic potential. Similarly, if even one human over the age of 30 has no symptoms of FDS, it proves not only that that subject has an effective maintenance system, but also that all of us have that genetic potential.

Where, as here, the question is one of genetic potential there can be no anomalies. If dysfunctionality is something that is genetically designed to occur only in old people, then, barring some genetic defect (or other environmental cause), no young person would suffer from dysfunctionality. Intrinsic damage is an inexorable force. The only way it would be possible for any older person to be healthy and strong is if that person has an effective maintenance system. And the principles of evolution dictate that if one person has an effective maintenance system, we all have that genetic potential.

One commentator who supports the PA point of view describes the NPA approach to be one of eliminating PA as an alternative, and then “devising the least implausible non-programmed theory and then constructing the least implausible interpretations of empirical evidence that support the theory.” Goldsmith TC, On the programmed/non-programmed aging controversy, Biochemistry (2012).
Gladyshev VN, Aging: progressive decline in fitness due to the rising deleteriome adjusted by genetic, environmental, and stochastic processes, Aging Cell (2016).

The next essay in this Section is “Paradigmatic Norms and Paradigm Paralysis.”