It’s a myth that you get a new body every 7-10 years. The reason is, different cells last different lengths of time. Colon cells last only about four days, skin cells two to three weeks, and neurons a lifetime. In that, the body you are in now is not the same as it was last week, last month, or last year, although it feels the same. So are you truly the same person?
It may predate him, but the ancient Greek historian Plutarch was the first to write this intriguing thought exercise down. It’s called the Theseus Paradox or the ship of Theseus. A hero of Greek mythology and the supposed founder of Athens, Theseus is said to have won a number of naval battles and defeated several monsters, including the Minotaur. Plutarch’s recording of the memorial set up to honor this epic founder has had great thinkers scratching their heads for millennia since.
The ship wherein Theseus and the youth of Athens returned 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, insomuch 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.
-Plutarch (Vita Thesei, 22-23)
Model of a Greek trireme. Credit: Deutsches Museum, Munich, Germany.
The memorial remained floating in Athens harbor for centuries, according to Plutarch. It’s said to have been erected during the lifetime of Demetrius Phalereus, a famous statesman and writer, who was thought to have walked the earth around 350-280 BCE. Over time, the ship’s boards began to rot. Like with the upkeep of any important monument, these were replaced.
At some point, all the boards in the ship must’ve been switched out. So the vital question is, is it still the same ship? If not, at what point does it cease to be the ship of Theseus? Replacing one board may not be such a big a deal. But what about when half of them are no longer original, most of them, or all of them? In a way, human life is like this.
Some philosophers say we are our body. But as we grow older, we get wrinkles and gray hair. We develop health problems and modify our diet. We change our look, our clothes, our hairstyle, and more. And then there’s the death and replacement of most of our cells. So our body isn’t a permanent fixture. Others say our mind is what gives us our identity. Yet, our outlook on life changes over time. We may become an addict or get sober, find religion or lose it, just as we maybe become jaded... or embrace an unbridled optimism.
There are those who say our title, occupation, position, and responsibilities lend us identity. And even so, we may have different friends in years to come or a different spouse. Our children will grow up and move away. And our career likely will not stay the same, either. On average, a person changes careers 5-7 times in their lifetime and has 11.7 jobs. That’s impressive, considering how much of our identity is derived from our work and career. We may move to another city or even the other side of the world. So with all of these changes, are we really the same person throughout? If not, which version is the real you? Is there one? There are many ways to answer.
Unlike a statue which is frozen in time, one of the only real constants in human life is change. But if that’s so, then what is our true identity and how may we get to know it? Credit: Getty Images.
Some philosophers say changing one plank alters the ship irrevocably. Others say if at least one original plank is still in the ship, it’s the real deal. Then there are those who posit that the monument remains Theseus’s ship throughout. Try as they might, it’s hard to pin down exactly why a gradual change is okay, while a sudden one feels unacceptable. Consider how shocking it is when someone has an accident, say a head trauma, and they wake up a completely different person. Yet, if they made the same changes gradually over time, we wouldn’t find it particularly jarring. One common answer is known as Spatio-temporal continuity.
This says that all objects change continuously as they travel through space-time. As such, they’ll have parts replaced from time to time, may even change form or composition. Yet, their identity remains. The famous Greek philosopher Heraclitus posited that we don’t step in the same river twice. Everything is constantly changing, though we’re not likely to notice. The equivalent in our species can be summed up very well in a statement by Harvard psychologist Daniel Gilbert. He said, “Human beings are works in progress that mistakenly think they’re finished.”
Many philosophers have put their own spin on the Theseus paradox over the years. 17th century English philosopher, scientist, and historian Thomas Hobbes, for instance, wrote a version where a collector took all the original boards that were replaced and one-by-one, built a second ship of Theseus. So which ship is the actual one, the immaculate memorial in the harbor or the rotting one in the dry dock? There is no right answer. What this paradox reminds us is, although we see identity as a fixed and solid structure, it’s actually thin, malleable, and ever-changing.
To learn more about the Theseus paradox, click here:
Cannabis Use Disorder, is that when you get so high you can’t figure out how to smoke anymore?
Cannabis use disorder, also known as CUD or cannabis/marijuana addiction, is a psychological disorder described in DSM 5 as "the continued use of cannabis despite clinically significant impairment." This includes people being unable to cut down on their usage despite wanting to, those who often use it despite finding it severely impairs their ability to function, or those who are putting themselves in danger to secure access to the drug.
While an understanding that marijuana can be addictive has existed for some time, and the image of the pothead who smokes so much they can hardly function is prevalent in our society, the effects of legalization on addiction rates have somehow gone understudied until now. Importantly, previous studies had failed to consider usage rates amongst populations over the age of 25.
In the new study, published in JAMA Psychiatry, focused on self-reported data on monthly drug use in four states where marijuana is now legal, Colorado, Washington, Alaska, and Oregon, from both before and after the drug was legalized in each state and compared it to others which have not yet legalized.
The data gave insights into the drug use habits of the respondents and specifically gave information about if they had smoked at all in the last month, the frequency of their drug use, and if they had ever had issues with how much they were using drugs.The researchers ultimately considered the responses of 505,796 individuals.
The increase in cannabis usage they found was considerable. The number of respondents over the age of 26 who claimed to have used the drug in the last month went up by 23% compared with their counterparts in states that have yet to legalize. Abuse of the drug by this group rose by 37%.
Teen usage rose by 25%, and addiction rates rose as well. This increase was small, though, and the authors have suggested it may be due to an unknown factor. The rate of usage or abuse for respondents between the ages of 18 and 25 did not increase at all.
After breaking the results down by demographics, the primary finding held; adults over the age of 26 are using marijuana more often when it is legalized, and they are starting to use it too much.
The grain of salt
As in any study where findings are self-reported, the exact numbers you see here should be taken with a grain of salt. They could be slightly higher or lower. As this study relies on people self-reporting their usage of a drug that is still illegal in many places, it is very possible that the apparent spike in addiction rates is caused by more accurate reporting, as people who live in an area where pot is still illegal may be less likely to report smoking it every day.
And it should be repeated a thousand times over that correlation and causation are not the same thing. There could be some unknown factor causing these increases in each case.
Despite these qualifications, the study is still useful in giving us a general sense of what may happen in states that have yet to legalize.
What does this mean for society and drug users?
While claims of "reefer madness" are greatly exaggerated, marijuana has several well established and thoroughly studied side effects. While occasional use isn't terribly harmful, addiction can be. Lead author Magdalena Cerdá of New York University explains in the study that heavy marijuana use is associated with "psychological and physical health concerns, lower educational attainment, decline in social class, unemployment, and motor vehicle crashes."
A substantial increase in the number of people who are addicted to the stuff will incur costs to society down the line.
Of course, a 37% increase in problematic usage means that the percentage of adults smoking too much went from .9% to 1.23% of the population responding to the survey. This makes it far less prevalent than issues with alcohol, which affected around 6% of all Americans in 2018.
Recently, Big Think's Philip Perry wrote a piece about how legalization could improve the health of millions by allowing the government to regulate the purity of commercially sold marijuana. This remains true. However, it must be weighed against the findings of this study, which suggests that at least some of these health gains will be wiped out by increased addiction rates.
What does this mean for legalization efforts?
The legalization steamroller will undoubtedly keep rolling along. While health concerns are one factor in the debate over marijuana, it is only one of many. In Illinois, where I live, weed will become legal on January 1st of 2020. The legalization campaign and legislation were more concerned with issues of social justice, the failures of prohibition, and finding a new source of tax revenue (since we're half broke) than with matters of potential addiction.
As Vox reports, the authors of the study aren't suggesting that legalization shouldn't take place; that is another, broader debate. They merely wish to present the fact that legalization has a particular side effect that we should be aware of.
While this study is unlikely to change anybody's stance on if weed should be legalized or not, it does show us a critical element to be considered when discussing drug policy. No drug is perfectly safe, and we have reason to believe that legalizing marijuana will mean that more people will have a hard time with it. Let's hope that legalization proponents keep that in mind as they rack up their victories.
It's definitely happening, and it's definitely weird. After the apparent death of some monks, their bodies remain in a meditating position without decaying for an extraordinary length of time, often as long as two or three weeks.
Tibetan Buddhists, who view death as a process rather than an event, might assert that the spirit has not yet finished with the physical body. For them, thukdam begins with a "clear light" meditation that allows the mind to gradually unspool, eventually dissipating into a state of universal consciousness no longer attached to the body. Only at that time is the body free to die.
Whether you believe this or not, it is a fascinating phenomenon: the fact remains that their bodies don't decompose like other bodies. (There have been a handful of other unexplained instances of delayed decomposition elsewhere in the world.)
The scientific inquiry into just what is going on with thukdam has attracted the attention and support of the Dalai Lama, the highest monk in Tibetan Buddhism. He has reportedly been looking for scientists to solve the riddle for about 20 years. He is a supporter of science, writing, "Buddhism and science are not conflicting perspectives on the world, but rather differing approaches to the same end: seeking the truth."
The most serious study of the phenomenon so far is being undertaken by The Thukdam Project of the University of Wisconsin-Madison's Center for Healthy Minds. Neuroscientist Richard Davidson is one of the founders of the center and has published hundreds of articles about mindfulness.
Davidson first encountered thukdam after his Tibetan monk friend Geshe Lhundub Sopa died, officially on August 28, 2014. Davidson last saw him five days later: "There was absolutely no change. It was really quite remarkable."
The science so far
Credit: GrafiStart / Adobe Stock
The Thukdam Project published its first annual report this winter. It discussed a recent study in which electroencephalograms failed to detect any brain activity in 13 monks who had practiced thukdam and had been dead for at least 26 hours. Davidson was senior author of the study.
While some might be inclined to say, well, that's that, Davidson sees the research as just a first step on a longer road. Philosopher Evan Thompson, who is not involved in The Thukdam Project, tells Tricycle, "If the thinking was that thukdam is something we can measure in the brain, this study suggests that's not the right place to look."
In any event, the question remains: why are these apparently deceased monks so slow to begin decomposition? While environmental factors can slow or speed up the process a bit, usually decomposition begins about four minutes after death and becomes quite obvious over the course of the next day or so.
As the Dalai Lama said:
"What science finds to be nonexistent we should all accept as nonexistent, but what science merely does not find is a completely different matter. An example is consciousness itself. Although sentient beings, including humans, have experienced consciousness for centuries, we still do not know what consciousness actually is: its complete nature and how it functions."
Consciousness
As thukdam researchers continue to seek a signal of post-mortem consciousness of some sort, it's fair to ask what — and where — consciousness is in the first place. It is a question with which Big Think readers are familiar. We write about new theories all the time: consciousness happens on a quantum level; consciousness is everywhere.
So far, though, says Tibetan medical doctor Tawni Tidwell, also a Thukdam Project member, searches beyond the brain for signs of consciousness have gone nowhere. She is encouraged, however, that a number of Tibetan monks have come to the U.S. for medical knowledge that they can take home. When they arrive back in Tibet, she says, "It's not the Westerners who are doing the measuring and poking and prodding. It's the monastics who trained at Emory."
It is that time again when we watch in awe as Olympic athletes perform dazzling feats of athletic prowess. But as we stare in rapt attention at the speed, grace, and strength they exhibit, it is also a good time to pay attention to how they embody, literally, fundamental principles that shape the entire universe. Yes, I'm talking about physics. On our screens, these athletes are giving us lessons in the principles that giants like Isaac Newton struggled mightily to articulate.
Naturally, there are many Olympic events from which we could learn some basic principles of physics. Swimming shows us hydrodynamic drag. Boxing teaches us about force and impulse. (Ouch!) But today, we will focus on gymnastics and the cosmic importance of the conservation of angular momentum.
The conservation of angular momentum
Much of the beauty of gymnastics comes from the spins and flips athletes perform as they launch themselves into the air from the vault or uneven bars. These are all examples of rotations — and so much of the structure and history of the universe, from planets to galaxies, comes down to the physics of rotating objects. And so much of the physics of rotating objects comes down to the conservation of angular momentum.
Let's start with the conservation of regular or "linear" momentum. Momentum is the product of mass and velocity. Way back in the age of Galileo and Newton, physicists came to understand that in the interactions between bodies, the sum of their momentums had to be conserved (which really means "does not change"). This is a familiar idea to anyone who has played billiards: when a moving pool ball strikes a stationary one, the first ball stops while the second scoots away. The total momentum of the system (the mass times velocity of both balls taken together) is conserved, leaving the originally moving ball unmoving and the originally stationary ball carrying all the system's momentum.
Credit: Sergey Nivens and Victoria VIAR PRO via Adobe Stock
Rotating objects also obey a conservation law, but now it is not just the mass of an object that matters. The distribution of mass — that is, where the mass is located relative to the center of the rotation — is also a factor. Conservation of angular momentum tells us that if a spinning object is not subject to any forces, then any changes in how its matter is distributed must lead to a change in its rate of spin. Comparing the conservation of angular momentum to the conservation of linear momentum, the "distribution of mass" is analogous to mass, and the "rate of spin" is analogous to velocity.
There are many places in cosmic physics where this conservation of angular momentum is key. My favorite example is the formation of stars. Every star begins its life as a giant cloud of slowly spinning interstellar gas. The clouds are usually supported against their own gravitational weight by gas pressure, but sometimes a small nudge from, say, a passing supernova blast wave will force the cloud to begin gravitational collapse. As the cloud begins to shrink, the conservation of angular momentum forces the spin rate of material in the cloud to speed up. As material is falling inward, it also rotates around the cloud's center at ever higher rates. Eventually, some of that gas is going so fast that a balance between the gravity of the newly forming star and what is called centrifugal force is achieved. That stuff then stops moving inward and goes into orbit around the young star, forming a disk, some material of which eventually becomes planets. So, the conservation of angular momentum is, literally, why we have planets in the universe!
Gymnastics, a cosmic sport
How does this appear in gymnastics? When athletes hurl themselves into the air to perform a flip, the only force acting on them is gravity. But since gravity only affects their "center of mass," it cannot apply forces in a way that changes the athlete's spin. But the gymnasts can do that for themselves by using the conservation of angular momentum.
By changing how their mass is arranged, gymnasts can change how fast they spin. You can see this in the dismount phase of the uneven bar competitions. When a gymnast comes off the bars and performs a flip by tucking their legs inward, they can quickly increase their rotation rate in midair. The sudden dramatic increase in the speed of their flip is what makes us gasp in astonishment. It is both scary and a beautiful testament to the athletes' ability to intuitively control the physics of their bodies. And it is also the exact same physics that controls the birth of planets.
"As above so below," goes the old saying. You should keep that in mind as you watch the glory that is the Olympics. That is because it is not just athletes that have this intuitive understanding of physics. We all have it, and we use it every day, from walking down the stairs to swinging a hammer. So, it is no exaggeration to claim that the first place we came to understand the deepest principles of physics was not in contemplating the heavens but moving through the world in our own earthbound flesh.
