By LUIZ MENNA-BARRETO*

There is a notable lack of reflections on the changes observed in the increase in life expectancy from an evolutionary point of view.

My motivation to write this account, partly very personal, emerged on my 78th birthday, in October 2024. Despite the fact that I have been clearly aging in recent times, the motivation was lacking, perhaps because I understood this account as useless, possibly redundant with what is read out there. A second motivation, now of a more general nature, was to share with potential readers my choice of dialectics as a tool/method for looking at and interpreting realities. The dialectical approach will appear both in the account of my personal experience and in my reading on the evolutionary meaning of aging.

To the potential reader of these memoirs, I would like to warn that this is a set of markedly personal perceptions, and therefore cannot be generalized. In fact, any account of the processes experienced by our body is always marked by the singularity of our life stories. The choice of the expression “ongoing process” already contains this warning of the essentially dynamic nature of the processes of our bodies, seen both from the point of view of the species and from the point of view of individuals.

Aging and death are characteristics of living matter, and their functionality is linked to the evolution of that same living matter. Each generation carries inherited characteristics, but also adaptive mechanisms that favor changes of direction over time. The increase in life expectancy is perhaps a good example of the relative plasticity of the process, especially in countries where improvements in quality of life are notable.

And why dialectics? It is a philosophical and ideological option, with obvious Marxist inspiration, situated in the field of historical materialism. I cultivate the understanding that each and every function of our bodies carries this double historical burden, the phylogenetic, long-term, and the ontogenetic, shorter-term, times that are expressed simultaneously.

For those who are not familiar with this time-based reading of organisms, I like to give an example of a human function: language. The ability to perceive and emit sounds and attribute meanings to these sounds is a trait we inherit at birth, while the language we will speak comes with the social experience of each human being. Dialectics is a method that invites us to think about bodies and, why not, about things and events involving bodies and things, always loaded with stories that help us define both bodies and things.

Well, I have been experiencing positive and negative aspects of “getting old,” joys and sadnesses that are dated to the changes I have gone through along the way in life. The first change I want to comment on is that of memories, a very present and frequent change in recent events – I think I have seen this film, but I am not sure, and it turns out I watched it the week before. When I have seen it and rewatch it, the memory of having seen the film gradually comes to me until it becomes certain – yes, I have seen this film.

My memory of the routes I take on the city streets is also compromised, which makes me feel unsafe even when I travel frequently on the streets of Mogi das Cruzes, where I have lived for over 20 years. It is true that the city streets, as well as the sidewalks, especially in the city center, are very old, narrow and poorly maintained. It is not uncommon for me to get lost on these routes, which are full of one-way streets – even though I would quickly learn the routes I took when visiting an unfamiliar city.

On the other hand, events from my childhood often come to mind, events that seemed doomed to disappear now appear very clearly. I cannot relate these recovered memories to significant events; the process seems to be more random. I like to think that this randomness can be interpreted as the way we operate memories; improbable paths open space for creativity contained in unprecedented associations.

If my reading makes any sense, the attribution of specific meanings to dreams, for example, in the field of psychoanalysis, tends to be incomplete. Meanings that fail to recognize randomness seek to affirm a logic that is sometimes nonexistent, but above all limited. I would like to clarify that my reading of this randomness does not imply ignoring the fecundity of both psychoanalytic and neuroscientific methods and knowledge.

What seems interesting to me is to associate this knowledge, understanding that memories can, perfectly and finally, only make sense in this association, that is, when memories have a history. In the case of neuroscience, the location of singular memories in discrete regions of the cerebral cortex, respectable due to the effort required, carries inheritances of both the species and the individual. I believe that we construct our individual memories involving different regions of the brain, a fact that imposes limitations on attempts to generalize findings, attributing individual characteristics to the entire species.

What you, the reader, have just read is an example of my dialectical exercise on memory. Some recent articles on olfaction and dreams have been published with interpretations that tend to overcome narrow conceptions of the olfactory function and its infrastructure in the human brain. The mapping of changes in the functioning of brain areas, recently published (Ward et al, 2023) in which the authors refer to associations between odors and visual and verbal perception also brings this limitation of generalization: ignoring the history of individual experience in brain functioning.

Much of what is currently published about aging is based on data on the incidence of pathologies in the elderly (Ikram, 2024), but there is a notable lack of reflections on the changes observed in the increase in life expectancy from an evolutionary point of view. After all, if death is, so to speak, genetically programmed, its specific (individual) limits seem to make this determination more flexible (Tacikowski, 2024).

However, there are essays on the fatality of individual death, but few question the evolutionary role of this fatality, with the exception of Stanley Shostak's book (2006). This gap in the academic literature is most likely related to the dominant individualism in our culture, closely linked to the current socioeconomic model known as neoliberalism.

In addition to privileging a worldview limited to our immediate interests (almost always linked to the consumption of material goods), this view ends up hiding/inhibiting the evolutionary reading of both life and death. This is therefore a contradiction between the individual and collective reading of aging, with an evident disproportion between the first, dominant, and the second, inferiorized.

*Luiz Menna-Barreto is a retired “senior” full professor of biomedical sciences at EACH-USP. He is the author, among other books, of History and Perspectives of Chronobiology in Brazil and Latin America (Edusp). [https://amzn.to/4i0S6Ti]

References

Tacikowski, P., Kalender, G., Celiberti, D. and Fried, I. Human hippocampal and entorhinal neurons encode the temporal structure of experience.

Nature volume 635, pages 160–167 (2024)

Shostak, S. The Evolution of Death – Why We Are Living Longer.

The State University of New York, SUNY series in Philosophy and Biology, 2006

Ward, R.J., Ashraf, M., Wuerger, S., and Marshall, A. Odors modulate color appearance. Front. Psychol., 05 October 2023 Sec. Cognitive Science Volume 14 – 2023 https://doi.org/10.3389/fpsyg.2023.1175703

Ikram, M.A., The use and misuse of “biological aging” in health research. Nature Medicine, v. 30, p. 3045, 2024.

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