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Nate Smith

Stopping Aging

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Hello Dr. RJM,

Do you believe that mankind will ever develop the ability to stop or reverse the aging process? In principle, is this possible?

I have heard that some scientists believe we are very close to doing so.

In simple terms, what are the primary barriers to overcome, and what are the mechanisms to do this?

Thanks.

Nate Smith

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Dear Nate,

You raised several good questions in one message. I will address each one individually.

"Do you believe that mankind will ever develop the ability to stop or reverse the aging process?"

Predicting what will happen is risky business, especially regarding life extension. Assuming that western civilization continues roughly as it is now, and noting the word "ever" in your question, my answer is "yes".

"In principle, is this possible?"

Yes, absolutely! Mortality must be regarded as metaphysically given, but aging belongs to the realm of scientific inquiry. If this answer is confusing, I will welcome a follow-up question.

"I have heard that some scientists believe we are very close to doing so."

That belief has been prevalent for hundreds of years, at least, but let me note with emphasis that everyone (with documentation) who was born before 1890 is now dead. In other words, there is an exceedingly long history of failed predictions regarding life extension, which is the reason for my emphasis on the word "ever" in your first question.

I am very happy to have been born at a time when the kind of work needed to increase longevity was finally starting to be done, but it is a vastly complex field and I do not yet see human life extension in the offing. On the other hand, if anyone reading this is dismayed by my assessment, I should acknowledge that I made similar statements about animal cloning - six months before it happened. That time, I was wrong. The point is that the timing of landmark discoveries can be hard to predict, even for those working in a given field.

"In simple terms, what are the primary barriers to overcome, and what are the mechanisms to do this?"

The most fundamental problem is the complexity of the process involved, and the ways researchers can overcome that are (1) simple, hard work, and (2) taking the time to maintain a breadth as well as depth of knowledge. Having said that, I do also believe that the universities are a natural setting for the type of work that is needed, but government funding of research politicizes that setting to a considerable extent. If government grants were replaced by private, foundational support, I suspect that some of the participants and their priorities would change, and on balance we would probably make faster progress.

I could write more about the reasons why many scientists are optimistic at present, and more about technical barriers we need to overcome, but those topics each deserve several posts, so I will close this initial message here.

Sincerely,

RJM

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This topic came up in a casual conversation once (among myself and others that had no idea what we were talking about). My initial thoughts were these:

For the first twenty years or so of our lives, not only do we not undergo aging, but our bodies are actually improving. If physically, we have the ability to "fight off" the causes of aging, then with a little help, this process should be able to continue indefinitely. I at least convinced myself that, in principle, this should be possible.

The only counter argument I could think of to this was, what if there is some built-in genetic mechanism that, after a certain period of time, causes our body to shut down in certain ways? There are certainly genetically-timed developments we undergo (sexual development being an obvious one). I have no idea how much of aging is caused by external causes, and if any of it is caused by our nature.

What are your thoughts on these ideas?

Also, a few of things that I have heard of that contribute largely to aging are free radical (though I don't know much about what they are, or what they do) and the sun's radiation. Are there other larege contributors, and how do they affect aging?

Thanks again.

Nate Smith

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Dear Nate,

In the course of casual conversation, you touched on some of the major areas of research and topics of debate amongst experimental gerontologists.

"For the first twenty years or so of our lives, not only do we not undergo aging, but our bodies are actually improving. ... I have no idea how much of aging is caused by external causes, and if any of it is caused by our nature."

Our bodies are certainly growing and strengthening during the first twenty years, but that does not mean that aging has not already begun. The changes associated with maturation may simply be more prominent than the initial signs of aging occurring at the same time.

A key question is whether aging is genetically programmed, like development and maturation, or is a consequence of environmental factors, such as free radicals (which I will discuss in a separate message). If it is programmed, is the program a continuation of development or are other genes involved?

You will not hear the same answer from everyone in this field, but my current opinion is that aging is caused entirely by random, environmental factors. I am not aware of any evidence that there is a genetic program directing the aging process of any species in which it is fundamentally similar to human aging, either as a continuation of or transition from development, or as a separate process programmed by other genes.

Now, this position will startle some readers, because clearly there are genetic differences between species and among individual animals which may account for differences in their life spans. Indeed, mutations affecting just one gene can increase the life spans of lower animals, and studying such mutations is certainly a worthwhile branch of longevity research. What must be kept in mind is that these genetic variations affect the animals' resistance or ability to "fight off" the causes of aging, but it does not follow logically that either the variations or the genes themselves are the cause of aging.

To illustrate this point, consider a rough analogy with the wearing out of cars. Let's suppose that deterioration of the parts is caused by such things as gritty fuel, weather and friction during use, and that various makes and models of cars have different lifetimes because they are made of different types of metal, or their parts vary in thickness, texture, etc. In this case, I would not say that the deterioration itself is caused by the nature of the parts. It is caused by the grit and friction. The sturdiness of the parts may influence the rate at which the cause (grit) exerts the effect (deterioration), but with no grit there would be no deterioration, even for cheap cars.

Likewise, in the case of aging, genetic differences can reveal aspects of our make-up which limit our life spans, and potentially suggest what causal mechanisms underlie the aging process, but the weakest gene encodes only the parts most vulnerable to aging, not the agent to which the parts are vulnerable. The gene itself is not the damaging agent.

We must also remember that each actual animal has only one 'genotype' - one set of wheels, in the car example. Consequently, to extend the metaphor, we have to identify the counterpart of the grit in order to extend the total mileage of the car. We cannot convert it into a fancier model after it has been manufactured (and driven). The comparison of cars with similar motors but different fuel line durabilities and different lifetime mileages is useful, but only insofar as it focusses our attention onto the grit.

In a sense, I am suggesting that aging is externally caused, and not caused by our nature, although our nature determines how well and for how long we can resist the external causal agents. However, we must be careful with such formulations, because the antonym of 'external' is 'internal', and the changes taking place during aging are certainly internal to our bodies, and mostly internal to our cells.

Ultimately, all of the molecules being built up and broken down in cells have an external origin, and the parts which are already present are continuously changing and being changed by the parts coming from outside. In other words, what qualifies as an external versus internal agent of change ultimately becomes debatable: solar radiation would clearly be an external agent and a gene programming death at a specific age would be internal, but anything else would be ambiguous in such a classification.

To summarize, I do not think there is a built-in genetic mechanism that causes our bodies to shut down. Instead, I suspect that we do not have the ability to fight off the causes of aging fully, even at the outset. The extent to which aging is externally caused depends on what one considers to be an 'external' cause. Our nature determines only our resistance to aging, and is not itself the cause of aging.

Sincerely,

RJM

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Dr. RJM,

Without going too far from your field of expertise, what do you think about using the potential to stop aging as a selling point to help people appreciate the value of being rational? (i.e. the more rational a society, the more quickly new life-saving/enhancing technologies come about).

I think it has the potential to help Objectivism 'convert' the somewhat rational people who accept religion because of their fear of death.

Thanks

Scott Schiff

Overland Park, KS

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Dear Scott,

I agree that there are probably people who accept religion, at least in part, because of their fear of death. Indeed, sometimes during my childhood, I myself wished that I could accept religion for precisely that reason. Subsequently, I decided that becoming religious would be an even more fearful prospect than death. In either case, one becomes totally cut off from reality, but at least death would not involve a loss of sanity and self-respect (both of which are associated with religious faith in my mind).

I also agree that a more rational society is one in which new life-saving technologies will be developed more quickly, but that kind of rational argument is not likely to convert someone who places the primacy of consciousness before rational argument as such, particularly if fear is the motivation. Such anxiety would probably be too deeply rooted to be overcome by the *potential* to stop aging. If we could *actually* stop or slow the aging process, then the cause of the anxiety would be removed, or at least it would become more remote, and then the influence of religion might be expected to wane.

Having said that, I should emphasize two points. First, we are really talking about psychology here, and that is not my area of expertise. Of course, my willingness to speculate about the effect of breakthroughs in this research area on a hypothetical person's beliefs, assumed for the sake of argument, should not be taken to endorse guesses or assumptions about the motivation of any actual religious person. Second, there is a philosophical issue which I believe is more fundamental than either the biomedical or psychological issues: using anything "as a selling point to help people appreciate the value of being rational" is unlikely to work, because it implies that you are using reason to argue for reason. If the person does not already accept reason as an absolute, then by definition argument and persuasion cannot be expected to influence his beliefs.

If this answer prompts any related questions, then I think we should use a different topic title. Something like 'Aging and Rational Values' or 'Philosophical Implications of Longevity Research' would be appropriate.

Sincerely,

RJM

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Dr. RJM,

I was wondering what external factors you were referring to. You mentioned sunlight, and I think you hinted at the nature of substances coming into the body from the outside world. To what extent is aging caused by stress and the way the body deals with stress? I know that the presidency, for example, is said to and seems to age people.

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Dr. RJM,

In your professional opinion, since external factors are the cause of aging, is there any particular external factor that we should all avoid exposure to? What would be the worst offenders? Should I stay out of the sun? Lay off the bacon cheeseburgers? B)

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Dear un-skinned-alive, and Inspector,

I think the main external factors responsible for aging are the food we eat and the air we breathe - and I don't mean impurities, I mean the food and air themselves. The reason is that the process of extracting energy from the food carries a risk of side reactions which generate free radicals, which then cause structural damage to the constituents of the cell. Not all of the damage is detected, and not all of the damaged molecules are repaired or replaced. Some of the resulting modifications are harmless and a few are very harmful, but the cumulative effect is an increasing likelihood of disease and a decreasing ability to recover (at the cellular level and at the whole-animal level).

I agree that sunlight, other sources of radiation, and stress are all contributors to this process, and contaminants or toxins in food and air should not be completely ignored, but the major contributors are likely to be things we cannot control by changing our behaviour. Damage and aging may be caused as side effects by food, air and sunlight, but those things are also good, indeed essential (although I will say that I try to limit my exposure to sunlight, and rely more on fortified milk for vitamin D).

The objective of slowing the aging process is further complicated by the fact that free radicals are actually generated on purpose in the body, as a mechanism of regulation of gene expression and to kill bacteria. That implies that we should attempt to repair the damage which occurs as a side effect, rather than trying to prevent it. However, most forms of damage which occur with any degree of regularity, i.e. damage to particularly sensitive targets, are ones for which we have already evolved repair mechanisms. It is not yet clear that improving the efficiency of existing repair mechanisms is necessary, because they appear to operate below their maximum capacity under normal conditions, and it is difficult to design new ones, because they would have to counteract comparatively rare lesions or complex, random aggregates of cellular "garbage". There are various ways we can imagine to bypass these problems, and one of them may very well become a major breakthrough, but so far that has not happened.

I hope this message goes some way toward explaining why it is difficult for me to anticipate dramatic increases in longevity in the foreseeable future. As for the estimated timing of the breakthrough: next month or next century, but probably somewhere in between.

Sincerely,

RJM

Note: I will post separately about diet, but not specifically about bacon cheeseburgers (!), in a message to Glenn Martin under the subject heading "Healthiest Diet for Humans". I had a very good discussion about stress with Ray Kilmer and Stephen and Betsy Speicher in the "Facts - Science - Biology & Medicine" subforum, March 3-6, under the heading "aging, genes/stress". I refer interested readers to that discussion, but we could continue here, with "Stress" as a topic title, if there are any follow-up questions.

Concerning premature aging due to the stresses of leadership, Woodrow Wilson of the USA and George VI of the UK are the most widely-recognized and convincing examples, but some presidents and prime ministers have apparently experienced much less stress, allowing them to live into their 80s or 90s.

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