Turnover rate

Artistic depiction of atomic turnover
(atoms falling and floating off the body of each molecule)
atomic turnover
Depiction of the "evolution of the human molecule" by Canadian communications designer Shawn LaPaix, a spin on English biologist Thomas Huxley’s famous 1863 evolution of man drawing, using the 1952 CPK atomic color scheme: red = oxygen, blue = nitrogen, gray = hydrogen, black = carbon (not shown); for a poster for the 2005 University of British Columbia Art Gallery exhibit “The Human Body in History”, alluding to the idea that human is a body of evolving atoms, formed into the structure of a molecule, that has been chemically synthesized into its current form, over long spans of evolutionary time. [4]
In hmolscience, turnover rate refers to the number of atoms that "turn over", annually or biannually, in the physical body of a human, or powered animate-reactive CHNOPS-based molecule, e.g. one human molecule (person), per unit time period, often quantified annually (Aebersold, 1949).

Overview
In 2007, Terrence Sejnowski, American computational neuroscientist, stated the following about turnover, in respect to memory mechanism:

“I have been puzzled by my ability to remember my childhood even though most of the molecules in my body today are not the same ones I had as a child—in particular the molecules that make up my brain are constantly being replaced with newly minted molecules—despite this molecular turnover, I have detailed memories of places where I lived fifty years ago.”

In the human molecule, the turnover rate of atoms in the body is 98%, meaning that every year, the typical person acquires nearly an a complete set of the 26-elements that comprise the person. [1]

Heraclitus river paradox | Ship of Theseus
The philosophical paradoxes associated with atomic turnover in things that grow or powered metabolic organisms, such as whether a person is still the same person they were a year ago, was first captured in the ancient Greek philosophical debate about whether "river", with new water continuously flowing through it, or a "ship" (or carriage), with its parts continuously replaced, is the same ship or river, a paradox discussed by philosophers including: Heraclitus, Socrates, and Plato.

Greek "flux and fire" philosopher Heraclitus, for instance, attempted to solve the paradox by introducing the idea of a river where water replenishes it, arguing, as quoted by Greek philosopher Arius Didymus, that "upon those who step into the same rivers, different and again different waters flow", which has come down to us as the motto: “you never step in the same river twice.”

Socrates and Plato, supposedly, discussed the paradox in terms of the exchange the parts of their “carriages”, one by one until, finally, Socrates's carriage is made up of all the parts of Plato's original carriage and vice versa, after which the he question becomes: if or when did they exchanged their carriages.
Ship of Theseus
A word scramble representation of the ship of Theseus, made of replaceable parts: sails, mast, and planks, the philosopher's model for the query about "things that grow" and whether they are same things when all the parts have been replaced?

Greek historian philosopher Plutarch, supposedly, disputed Heraclitus' claim about stepping twice into the same river, citing that it cannot be done because “it scatters and again comes together, and approaches and recedes.” He eventually summarized the paradox in the form of the the story of the ship of Theseus, which had its parts continuously replaced each time one broke or rotted, after which philosophers began to puzzle as to whether it was really the same ship:

“The ship wherein Theseus and the youth of Athens returned from Crete had thirty oars, and was preserved by the Athenians down even to the time of Demetrius Phalereus, for they took away the old planks as they decayed, putting in new and stronger timber in their place, in so much that this ship became a standing example among the philosophers, for the logical question of things that grow; one side holding that the ship remained the same, and the other contending that it was not the same.”

This ship question came to be known as “Theseus’s paradox”. [13]

Modern variants of Theseus’ paradox have been discussed by Thomas Hobbes and John Locke. [14]

Slosson | Fallacy of materialism
American religion reconciling chemist Edwin Slosson seems to have been the first to discuss atomic turnover in parts of the human; though it remains to be discerned from where he gets his statistics, as he cites rarely. In 1903, Slosson penned his “The Chemistry of the Greatest Miracle in the Bible” article, in which he interjects on the famous Genesis 2:7 Bible statement: “And God formed man out of the dust of the ground”—which, as Slosson seems to have been unaware, is but a Christian re-write of the Egyptian clay creation myth—in modern chemistry and atomic turnover rate terms, albeit themed in terms of chemical miracles, in respect to the so-called "nonliving" to "living" transformation of the atoms into moving animated humans. To begin with, Slosson states: [15]

“Each one of us was created out of the dust of the earth, not thousands of years ago, but within the last few years.”

Slosson then, after discussing how the air we breathe is four-fifths nitrogen and one-fifth oxygen, both in “nonliving” state, and that we can only absorb the oxygen but not the hydrogen by breathing, fumbles out the following, which he says occurs as a "miracle" twenty times a minute when we breathe:

“Some particles of nonliving matter are drawn into our bodies and become the medium of life, motion and thought. Just as often the reverse process is repeated. Particles of carbon which have formed part of our living bodies are thrown off with every breath, rapt away by the atoms of oxygen, and sink into the nirvana of the inanimate world, changing their allegiance from the animal to the vegetable kingdom. This transformation of living to nonliving matter is just as great a miracle as the reverse process, when you think of it. We can no more understand how we can die than how we can live. People say we die but once. Really we die every few years just as completely as we ever shall.”

This, of course, is parlay into the defunct theory of life position. In any event, he continues:

“Not all parts of the body wear out equally fast and have to be renewed as frequently. The more mobile and softer tissues change most rapidly. The blood is altering in composition constantly. But even the particles of lime, carbon and phosphorus in the solidest bone are continually being taken out and replaced by new ones, just as they change a railroad bridge, piece by piece, without tearing it down and interrupting the traffic at any time. In the external parts of the body we can see this for ourselves. We get entirely new fingernails every four or five months, and new toe nails once a year. Our eyelashes last us only about a hundred days, and we get a new skin oftener than we get new clothes—that is, most of us—for that is renewed every month. The only part of the body that is not completely changed in the course of a few years (which popular belief places at the magical number of seven) is the enamel of our teeth.”

On this basis, Slosson interjects with some humor:

“So it would seem that since we are not composed of the same material we cannot be the same persons we were years ago. According to this view, no man ought to be held to a contract longer than, say, seven years at most. If a man is arrested for crime committed ten years ago he can easily prove an alibi. He can show that ever particle which constituted the man who did the deed has long since been dissipated and now forms part of the air, the sea, and the soil.”

This might be the origin of what some have called the “seven year replacement myth”. [8] The seven year turnover rate of atoms in the body, supposedly, dates back to a book from the 19th century. (Ѻ) Slosson continues:

“A man never celebrates his silver wedding with the same woman he married. He may call her his wife, but really he is not married to any part of her—except, as I said, to her teeth—and perhaps those are changed. Speaking from a materialistic point of view, a couple ought, for decency's sake, to have the ceremony performed over again every few years, so as to stay married.”

Slosson then gives his argument for what he calls the fallacy of materialism, as follows:

“Why is it that these things which are literally true seem to us so absurd? The reason is because of the very apparent fallacy. It is the fallacy of materialism. We know we are the same persons we were last year and the year before. Although we may have changed somewhat, we know it is not because we have new finger nails, new eyelashes and new everything. That did not change us. We know that if every molecule of our bodies were suddenly replaced by new molecules we should never know the difference. As the wisest of the Greeks said long ago: ‘the water changes, but the river remains the same.’ We really care nothing for the particular atoms of carbon, nitrogen, hydrogen and oxygen which make up what we mistakenly call ourselves. Let them go; we can get more: or if we cannot we do not want to keep these longer. We are not attached to the matter that composes our bodies.”

Slosson, in 1925, republished some of the above in his Sermons of a Chemist chapter on the chemistry of creation, outlining how finger nails renew ever four months, eyelashes every 150 days, skin once a month, with teeth enamel taking the longest to renew. [5]

Paul Aebersold (at computer)sodium turnover rated diagram
Left: American nuclear scientist Paul Aebersold (1910-1967) at his computer station, likely at the Oak Ridge National Laboratory, Tennessee, where at he did his pioneering experiments done with radioisotopes and the tracing of elements in and out of the body, finding that atoms in animate organisms have a 98 percent per year atomic turnover rate. [10] Right: Aebersold's 1949 diagram, from his “Atomic Energy Benefits: Radioisotopes” address, showing how an isotope of an atom, i.e. a "tracer atom", can be tracked in terms of the time it takes to move through the body. [16]
Aebersold’s radioisotope studies
In 1940s, American biophysicist Paul Aebersold, did the first work on the production and application of the radioactive materials (sodium-24 and phosphorus-32) administered to humans, for application and studies in medicine.

In 1949, Aebersold, in his “Atomic Energy Benefits: Radioisotopes” address, stated the following, based on his experiments at Oak Ridge National Laboratory, Tennessee, using radioisotopes and the tracing of elements in and out of the body: [16]

“The atoms now in your body are being replaced by new atoms at an amazingly rapid rate — at such a rate that in another year ... Before we go into more detail about the terrific traffic of atoms in your body — for that matter, the rapid atomic turnover in all forms of life, in even the simplest organisms — let us pause for some background information that may forestall the quite justified unbelief you may have concerning these startling facts. How do we know all this? How do we follow all the fast and complicated maneuvers that atoms enter into in our bodies and other complex systems?”

Then, following discussion about how radioactive forms (isotopes) of all of the elements can be artificiality made in an atomic reactor or pile, he explains how these radioactive elements can be measured as they leave the body via a Geiger counter:

“Once the sodium tracer atoms have been incorporated into a system we can study the rate at which they are eliminated. By studying the uptake and elimination, we can obtain the rate at which sodium atoms are replaced or turned over in the system. It is found that in a week or two, half of the sodium atoms that are now in our bodies will be replaced by other sodium atoms. Similar experiments with tracer hydrogen have shown that hydrogen atoms in our body are also quite rapidly replaced, half of them being replaced also in a week or two. Likewise it has been found that half the phosphorus in us now will have been replaced in a few weeks, and half of the carbon atoms in a month or two, and so on for nearly all the elements.”

Then, following a Zeno’s paradox like discussion about how atoms are replaced in decreasing fractional rates of time, he famously states:

“Theoretically we still have a small percentage of the same atoms in us that we had when we were born, but actually this percentage must be extremely small. In a year most of the atoms in us now—at least 98 percent of them—will have been replaced by other atoms that we take in via air, food, and drink.”

Aebersold, in short, found that 98 percent of all the atoms in a person’s body change out every year, and that within five years all the atoms had changed. [8] In the study, Aebersold fed radioactive atoms to people and or he injected them with radioactive atoms. Then using radiation detectors, he watched the atoms as they moved around. He'd watch them, for example, go up one arm, into the heart and down the other arm. [12]

Later citations
In 1954, Aebersold's study was made famous with the publication of the Time magazine article “Science: the Fleeting Flesh”, which stated, among other things, that: [9]

“The fastest-changing component, says Dr. Aebersold, is water. It forms about 70% of the body, and about half the water molecules are replaced every eight days. Other fleeting elements are carbon, sodium and potassium. The calcium and phosphorus in bones and teeth stay put longer.”

In 1955, Richard Feynman, in his “The Value of Science”, was discussing the turnover of atoms in his mind as follows: [19]

“The atoms that are in the brain are being replaced; the ones that were there before have gone away. So what is this mind of ours: what are these atoms associated with consciousness? Last week’s potatoes! They now can remember what was going on in my mind a year ago—a mind which has long ago been replaced. The think I call individuality is only a pattern or dance, that is what it means when one discovers how long it takes for the atoms of the brain to be replaced by other atoms.”

In 1965, American science writer George Harrison stated, in what likely is a concise summary version of the Aebersold study findings: [2]

“The body contains only 2 percent of the atoms that were spinning in it one year ago.”

This factoid became a popular re-quote; the following is one example from the new age publications:

“Quantum physicists have proven through radioactive isotope studies that 98% of the atoms in your body are replaced within one year. In three months your body produces an entirely new skeleton. Every six weeks, all the cells have been replaced in your liver. You have a new stomach lining every five days. You are continually replacing old blood cells with new ones. Your skin is sloughing off dead cells and producing a new skin monthly.”
Deepak Chopra (1989), Quantum Healing (Ѻ)

In 1995, biologist Lynn Margulis and science writer Dorion Sagan stated: [3]

“Every year, 98 percent of the atoms of your body are replaced.”

The utilization of this tool as a means to classify structured on the evolution timeline would seem to be an intuitive approach.

In 2002, American limnologists Robert Sterner and James Elser, in their 2002 book Ecological Stoichiometry, give the following note on turnover rate: [7]

"Perhaps you have noticed that our method of analysis does not consider the turnover rate of different biochemical pools. We did not take account, for example, the enormous differences between turnover rate of P within ATP compared to bone. Those turnover rates differ by many orders of magnitude (miniscule fractions of a second for ATP vs. months to years for bone). This was not an oversight. Ecological stoichiometry relates organism composition to its external environment, and hence it is the rates of demand and exchange of the whole living organism that we must focus on."

Activation energy
The general model as to how to go about quantifying atomic turnover in humans is that this factor plays a role in the activation energy of reactions between humans, in the sense that food intake and hence atomic turnover are a substrate factor, i.e. an interaction factor with the surface of the earth, which acts to facilitate human-human reactions, in the same manner as does the oxide-embedded iron surface, in the Haber process, act as a catalyst that works to lower the activation energy barrier to reaction between H2 and N2 just as does a fertile earth surface facilitate reactions between a male Mx and female Fy human molecule.

Philosophical implications
In 1949, Paul Aebersold, during his “Atomic Energy Benefits: Radioisotopes” address, diverged at one point into some philosophical implications about personhood: [16]

“Although next year you will be almost a completely new batch of atoms, you won’t be a new person. Your supercolossal traffic of atoms does not take place just by chance. It is very carefully regulated and controlled. In general, the atoms do not get very far off the right road, and there are no traffic jams. Next year we will appear much the same as we do now. Even though most of the atoms in our brain will have been replaced by other atoms, we will still go on remembering things that happened a long time ago. Also our emotions, reasoning, personality and individuality go on much the same. Physically we may be a new batch of atoms but unfortunately, perhaps, we are an old batch of emotions, ideas and reactions.”

Aebersold then goes on to dismiss the blind random chance model of evolution in general as follows:

“The more we study living things, the more we study all of nature, including the atom itself, the more we can see that everything is not just a matter of chance. Figure out the chance that some protein molecule, or some hormone, or vitamin or enzyme, for example, was gotten together by the mere chance meeting of all its component atoms out of a chaos of atoms. Such molecules are so complex that even over the period of billions of years since the earth was formed, it is still extremely unlikely that any such molecules would be formed by pure chance. It is even more inconceivable to believe that that chance can account for all the hundreds of thousands of types of molecules that occur in nature, for all the exceedingly dynamic and complicated processes which these molecules take part, and much less for all the marvels of biology.”

In 2007, NPR radio did a segment entitled “Atomic Turn-Up: How the Body Rejuvenates Itself”, wherein they had a sort of roundtable discussion on the subject with American chemist Logan McCarthy, a chemistry professor at Harvard University, on the subject of atomic turnover, American evolutionary biologist Daniel Dennett, among others. In the discussion, NPR science correspondent David Kestenbaum commented his concluding view that: [12]

“In a very real sense, we are not the people that we were a year ago. We're this collection of atoms that hang out together for a while and then they go on to do other things—sort of a momentary cloud of organization. So what is me? Am I still me if my parts have been replaced?”

Daniel Dennett replied to this: “Well, of course, the question goes way back to ancient philosophy.” They digress into science fiction discussion of teleportation and Kestenbaum comments that he knows of some Swedish researcher who found that some atoms do not turnover:

“It turns out there are some atoms that are with us for our entire life. This comes from a researcher in Sweden and the atoms are actually in some interesting places. They are deep in the DNA of some cells in our brain and in our heart, and also some atoms in our teeth.”

In conclusion of the interview, Debbie Elliot, the host, comments: “that is the temporary collection of atoms currently known as our science correspondent David Kestenbaum.”
CHNOPS turnover (and soul)
In recent years, the atomic turnover rate finding has been used in religion classes to spark discussions about (a) whether ‘we are this body’ or (b) whether we have some kind of spirit-soul, as one 2011 world religions student put it. [11] Left: cartoon from American philosopher Stephen Asma’s 2010 article “Soul Talk” on how the “mere mention of the soul” in his philosophy class “is like a spark that sets off dozens of combustions.” [18] Right: the atoms (elements), by percent mass, that a human or human molecule in totality is comprised of (see: hmolscience periodic table), which get completely replaced or "turned over" with new atoms every five years.

Religious implications
The experimental finding that atoms "turn over", that is enter and leave the body of a human at a measurable rate per second, day, or year has a number of significant implications, one of which is in the eventual downfall (or possible reformulation) of modern religion. To exemplify, as one Reddit.com poster queried in 2011, in the Ask Science section: [11]

“In my world religions class, the teacher presented an article that stated that 98% of atoms in the human body are replaced every year.”

The abstract of the article is:

“Studies at the Oak Ridge Atomic Research Center have revealed that about 98 percent of all the atoms in a human body are replaced every year. You get a new suit of skin every month and a new liver every six weeks. The lining of your stomach lasts only five days before it’s replaced. Even your bones are not the solid, stable, concrete-like things you might have thought them to be: They are undergoing constant change. The bones you have today are different from the bones you had a year ago. Experts in this area of research have concluded that there is a complete, 100 percent turnover of atoms in the body at least every five years. In other words, not one single atom present in your body today was there five years ago.”

This, according to the poster, “was to spark a discussion about whether ‘we are this body’ or whether we have some kind of spirit soul.” The poster objected to the statement, in his own words: “this seems incredibly unlikely and comes across as BS to me. Is this ‘cells in your body are replaced every 7 years’ statement true?”

These religious objections exemplify the collide between the views of the belief system of old world (Egyptian mythology told through the guise of Christianity, Islam, and Hinduism) and the new world (the periodic table / thermodynamic view of humans as surface-attached heat-driven animate molecules with atomic "turn over rate" whose so-called morality (or soul as it was called in olden days), or rather naturalness (as it is called in thermodynamics), is governed by the "moral symbols" of physical chemistry, as Goethe stated in 1809; and where "spirit", in some sense (or possibly not in any sense?), can be likened to the level of "animation" of a given animate molecule, so to speak—although, to note, the notion of spirit, as originally defined in the Egyptian seven component model of a human (ba, ka, etc.), is a bit of blurry subject to attempt to re-translate into physical chemistry terms.

In 2011, American philosopher Alexander Rosenberg, in his Atheist's Guide to Reality, discussed Theseus' ship paradox. [17]

Floating magnets | Electromagnetic field
One possible interjection into the turnover rate paradox is recourse to the famous pattern forming “floating magnetics experiment”, done originally by English chemist-physicist William Gilbert (c.1590), using floating loadstones, American physicist Alfred Mayer (1878), using negatively-charged needles on floating cork, and recently by Libb Thims (2014), using neodymium magnets on floating cork, according to which the electromagnetic field is what “holds” shapes of the positive and negative charges in regions of space, and that the geometric shape—like a person—will hold in form, if one charge is pushed into the pattern while another is removed:

magnet patterns

As magnets are added, as Mayer famously diagrammed (up to 20 magnets), the 3D pyramidal structure will grow geometrically: a triangle base at 3 magnets, a square base at 4 magnets, a hexagon base at 5 magnets, a two ringed structure base at 10 magnets, a center magnetic surrounded by two ringed base at 15 magnets, and so on. In this sense, one could conceptually understand the "structure holding" paradox if one were to add a base magnet to a given geometry while simultaneous removing one, and do this for all the magnets of the structure, similar to the ship, river, or carriage variants of the paradox, and then ask if the resulting turned over or magnetic replaced 3D geometric structure is the same growing "thing" or a different growing thing?

This model, naturally enough, can be scaled up to the people viewed as powered atomic geometries or human molecules, whereby the positively charged (floating) magnets and positively (hovering) magnets become atoms (elements), with varying amounts of positive or negative charged electron valency, albeit the description becomes more complicated owing to the effect that quantum electrodynamic changes are involved owing to cyclical sunlight photon input (cause) and resulting electron orbital transitioning (effect), whereby molecular animation results, something that does not occur in the magnet, ship, carriage, or river water scenarios.

Other
The 2013 Indian film Ship of Theseus (vid), is themed on people as reparable ships and the implications of human identity change in respect to morality, personal belief, and cornea, liver and kidney transplant of three different individuals. (Ѻ)

In 2015, in episode 5 of the show “Fortitude”, available on Amazon, that character Elena explains to Morton about how she’s made of atoms and how ever seven years all of her atoms change, refresh, or become new, and therefore that she has become new; the main dialogue is here: (Ѻ)

“I don't have any sort of relationship with Elena. None at all. You know, when I was in prison, I met this man, a man who tried to help me. A psychiatrist. He said to me that everyone is made up of many... Atomos? Aatoms? You understand? Atoms. Atoms. Atoms, yes. So for a human being it takes seven years before every atom, one by one, is replaced with a new one. So that means that after seven years this person... Is no longer that. So you are saying that Elena is a completely different person than Esmerelda. That's what you mean. Everything is changed. That is how you console yourself. That you've changed. That you are different. You are not that person anymore. Somebody else did it. You didn't do it. I am not her. Not anymore.”

This, supposedly, is a spin on the “my atoms made me do it” defense (see: killing spree paradox) and that after seven years, a prisoner can be pardoned for past crimes, because they are an atomically “new person” so to say.

See also
Turning tendencies

Ship of Theseus (film)
The 2013 film Ship of Theseus explores the human "identity" implications of the ship parts replacement paradox in respect to human body part transplants.
References
1. Thims, Libb. (2007). Human Chemistry (Volume One) (pg. 121). Morrisville, NC: LuLu.
2. Harrison, George. (1965). The Role of Science in Our Modern World (pg. 95). New York: William and Morrow.
3. Margulis, L and Sagan, C. (1995). What is Life? (pg. 17). University of California Press.
4. UBC (sample works) – ShawnLaPaix.com.
5. Slosson, Edwin. (1925). The Sermons of a Chemist (pg. 11). Harcourt, Brace, and Co.
6. Brockman, John. (2006). What We Believe But Cannot Prove: Science in the Age of Certainty (pg. 95). Perennial.
7. Sterner, Robert W. and Elser, James J. (2002). Ecological Stoichiometry: the Biology of Elements from Molecules to the Biosphere (chapter one) (turnover rate, pg. 77). Princeton University Press.
8. (a) Seaborg, Glenn T. (1968). “Paul C. Aebersold (1910-1967)” (abs), Radiation Research, 33(3): 677-79.
(b) Do We Replace Our Cells Every 7 or 10 years? (2010) (comment #20) – AskANaturalist.com.
9. Staff. (1954). “Science: the Fleeting Flesh”, Time, Oct 11.
10. The Paul C. Aebersold Papers – Cushing Memorial Library and Archives.
11. Are 98% of the atoms in the human body replaced every year? (2011) – RedIt.com.
12. Elliott, Debbie. (2007). “Atomic Turn-Up: How the Body Rejuvenates Itself”, NPR transcript, Jul 14.
13. Rosenberg, Alex. (2011). The Atheist’s Guide to Reality: Enjoying Life without Illusions (pg. 167). W.W. Norton & Co.
14. Ship of Theseus – Wikipedia.
15. Slosson, Edwin E. (1903). “The Chemistry of the Greatest Miracle in the Bible”, The Independent, 55:1454-61.
16. Aebersold, Paul C. (1949). “Atomic Energy Benefits: Radioisotopes”, address before the teachers in service course on atomic energy, Apr 7, New York City, in: Atoms at Work – Part I: Power From the Atom (by Dubridge), Part II: Atomic Energy Benefits: Radioisotopes (by Aebersold) (turnover rate, pg. 11, batch of atoms, pg. 13). Murray & Gee, 1950.
17. Rosenberg, Alex. (2011). The Atheist’s Guide to Reality: Enjoying Life without Illusions (pg. 167). W.W. Norton & Co.
18. Asma, Stephen. (2010). “Soul Talk”, The Chronicle Review, May 2.
19. (a) Feynman, Richard. (1955). “The Value of Science” (Ѻ), in: What Do You Care What Other People Think? (pgs. 240-48; quote, pg. 244). W.W. Norton, 1988.
(b) Norretranders, Tor. (1991). The User Illusion: Cutting Consciousness Down to Size (pg. 326). Penguin.
(c) Shlain, Leonard. (2009). Leonardo’s Brain: Understanding da Vinci’s Creative Genius (pg. 196). Lyons Press, 2014.

External links
Query: Theseus’ body, is there any part of a human that is cellularly or even atomically stagnant? (2003) – Reddit.com.

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