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This ancient thought exercise will have you questioning your identity
How much can something change and still be the same thing?
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:
A Mercury-bound spacecraft's noisy flyby of our home planet.
- There is no sound in space, but if there was, this is what it might sound like passing by Earth.
- A spacecraft bound for Mercury recorded data while swinging around our planet, and that data was converted into sound.
- Yes, in space no one can hear you scream, but this is still some chill stuff.
First off, let's be clear what we mean by "hear" here. (Here, here!)
Sound, as we know it, requires air. What our ears capture is actually oscillating waves of fluctuating air pressure. Cilia, fibers in our ears, respond to these fluctuations by firing off corresponding clusters of tones at different pitches to our brains. This is what we perceive as sound.
All of which is to say, sound requires air, and space is notoriously void of that. So, in terms of human-perceivable sound, it's silent out there. Nonetheless, there can be cyclical events in space — such as oscillating values in streams of captured data — that can be mapped to pitches, and thus made audible.
Image source: European Space Agency
The European Space Agency's BepiColombo spacecraft took off from Kourou, French Guyana on October 20, 2019, on its way to Mercury. To reduce its speed for the proper trajectory to Mercury, BepiColombo executed a "gravity-assist flyby," slinging itself around the Earth before leaving home. Over the course of its 34-minute flyby, its two data recorders captured five data sets that Italy's National Institute for Astrophysics (INAF) enhanced and converted into sound waves.
Into and out of Earth's shadow
In April, BepiColombo began its closest approach to Earth, ranging from 256,393 kilometers (159,315 miles) to 129,488 kilometers (80,460 miles) away. The audio above starts as BepiColombo begins to sneak into the Earth's shadow facing away from the sun.
The data was captured by BepiColombo's Italian Spring Accelerometer (ISA) instrument. Says Carmelo Magnafico of the ISA team, "When the spacecraft enters the shadow and the force of the Sun disappears, we can hear a slight vibration. The solar panels, previously flexed by the Sun, then find a new balance. Upon exiting the shadow, we can hear the effect again."
In addition to making for some cool sounds, the phenomenon allowed the ISA team to confirm just how sensitive their instrument is. "This is an extraordinary situation," says Carmelo. "Since we started the cruise, we have only been in direct sunshine, so we did not have the possibility to check effectively whether our instrument is measuring the variations of the force of the sunlight."
When the craft arrives at Mercury, the ISA will be tasked with studying the planets gravity.
The second clip is derived from data captured by BepiColombo's MPO-MAG magnetometer, AKA MERMAG, as the craft traveled through Earth's magnetosphere, the area surrounding the planet that's determined by the its magnetic field.
BepiColombo eventually entered the hellish mangentosheath, the region battered by cosmic plasma from the sun before the craft passed into the relatively peaceful magentopause that marks the transition between the magnetosphere and Earth's own magnetic field.
MERMAG will map Mercury's magnetosphere, as well as the magnetic state of the planet's interior. As a secondary objective, it will assess the interaction of the solar wind, Mercury's magnetic field, and the planet, analyzing the dynamics of the magnetosphere and its interaction with Mercury.
Recording session over, BepiColombo is now slipping through space silently with its arrival at Mercury planned for 2025.
Research suggests that aging affects a brain circuit critical for learning and decision-making.
As people age, they often lose their motivation to learn new things or engage in everyday activities. In a study of mice, MIT neuroscientists have now identified a brain circuit that is critical for maintaining this kind of motivation.
Why not just divide the United States in slices of equal population?
- Slicing up the country in 10 strips of equal population produces two bizarre maps.
- Seattle is the biggest city in the emptiest longitudinal band, San Antonio rules the largest north-south slice.
- Curiously, six cities are the 'capitals' of both their horizontal and vertical deciles.
Sweeping re-alignments<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yNDYwMTAwOC9vcmlnaW4ucG5nIiwiZXhwaXJlc19hdCI6MTYyMzU3ODA1NH0.u_5xakBvkYwgPtiwLU3z-1e082hBeqwS4Rl1uiJqdF4/img.png?width=980" id="23ff1" class="rm-shortcode" data-rm-shortcode-id="24a5b6ec251a11f3ed7aaefc205dde17" data-rm-shortcode-name="rebelmouse-image" alt="Printed in March 1812, this political cartoon was drawn in reaction to the newly drawn state senate election district of South Essex created by the Massachusetts legislature to favor the Democratic-Republican Party candidates of Governor Elbridge Gerry over the Federalists. The caricature satirizes the bizarre shape of a district in Essex County, Massachusetts, as a dragon-like "monster". Federalist newspaper editors and others at the time likened the district shape to a salamander, and the word gerrymander was a portmanteau of that word and Governor Gerry's last name." />
The original cartoon of the 'Gerry-Mander', published in 1812 in the Boston Centinel.
Image: Elkanah Tisdale (1771-1835), Public Domain.<p>One way for a political party to manipulate the outcome of elections is to 'gerrymander' electoral districts: manipulate their boundaries to increase the likelihood of a favorable outcome (see also #<a href="https://bigthink.com/strange-maps/53-ever-been-ger..." target="_blank">53</a>).</p><p><span></span>The term is almost as old as the United States itself, and the practice continues to disfigure the electoral map to this day. Perhaps these maps can serve as the inspiration for a radical solution. </p><p><span></span>They show the contiguous United States (i.e. without Alaska and Hawaii) sliced latitudinally and longitudinally into ten straight-bordered bands of varying size, so that each contains exactly 10 percent of the population. </p><p><span></span>Although certainly not intended as a reflection on electoral redistricting, it's tempting to see these sweeping re-alignments of the U.S. as a suggestion with some potential in that direction. </p>
United Strips of America<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yNDYwMTA4MS9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTY0NzE1MjQ1MX0.WpISo-g15B5O3qXbHXHf-7lQtAainpO7zPuizXWFOGs/img.jpg?width=980" id="d6656" class="rm-shortcode" data-rm-shortcode-id="72ed7c905283f9979ec0f82d451ad261" data-rm-shortcode-name="rebelmouse-image" alt="Reddit user curiouskip used U.S. Census population data to divide the 'Lower 48' into deciles (ten equal parts), each representing about 30.8 million people. Each decile is consigned its most populous city as 'capital'." />
The contiguous United States, divided into horizontal and vertical deciles.
Image: u/curiouskip, reproduced with kind permission.<p>Reddit user curiouskip used U.S. Census population data to divide the 'Lower 48' into deciles (ten equal parts), each representing about 30.8 million people. Each decile is consigned its most populous city as 'capital'.</p><p><span></span>Looking at the top map, which divides the U.S. into 10 longitudinal strips, we see</p><ul><li>Seattle rules the northernmost slice of territory. It is the broadest, and therefore also the emptiest one.</li><li>The Chicago, Omaha, New York City and Indianapolis strips complete the northern half of the country. And indeed: 50 percent of the population occupies roughly one half of the country, from north to south.</li><li>The dividing line between the top and bottom halves of the country runs from just north of the San Francisco Bay to halfway across the Delmarva Peninsula.</li><li>Capital cities of the southern strips are San Jose, Charlotte, Los Angeles, San Diego, and Houston.</li><li>The Houston Strip is divided into two non-contiguous areas. Florida maintains its panhandle, albeit much reduced. </li></ul><p>The bottom map shows the U.S. divided latitudinally into 10 bands of equal population. </p><ul><li>San Jose and Los Angeles both retain their capital status, this time of the two westernmost strips.</li><li>San Antonio is the main city of the Big Empty, more than twice as wide as the second-broadest band.</li><li>The dividing line between America's eastern and western half, population-wise, is far off-center: it skirts the eastern edge of Chicago, making the western half much bigger than the eastern one.</li><li>Houston, Chicago, and Indianapolis also remain the largest cities in their respective bands.</li><li>Further east, Jacksonville and Philadelphia get to rule over their strip of America, while Charlotte and New York City keep winning, both vertically and horizontally.</li></ul><p>Redistricting a country into zones of equal population – and that being your only criterium – will create districts that are randomly diverse, and perhaps also, at least in this case, unmanageably large. </p><p>However, mixing up the political map with a bunch of straight lines as the only instrument is something that has been considered before. Usually, the objective is the wholesale removal of age-old divisions. <br></p>
Perfectly square departments<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yNDYwMTEzOS9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTYwOTQyMzIwOH0.kYuf58g0bjsPL9DGPq5PycZ7PDJMnItT0rfrPonOP3k/img.jpg?width=980" id="89a68" class="rm-shortcode" data-rm-shortcode-id="5b81a43e785997bb1f11f72548659a9f" data-rm-shortcode-name="rebelmouse-image" alt="\u200bCh\u00e2ssis figuratif du territoire de la France partag\u00e9 en divisions \u00e9gales entre elles, proposition annex\u00e9e au rapport du 29 septembre 1789 \u00e0 l'Assembl\u00e9e nationale de la commission dite Siey\u00e8s-Thouret" />
France divided into 80-odd geometrical departments: failed proposal by Jacques-Guillaume Thouret (1790).
Image: Centre historique des Archives nationales – Atelier de photographie; public domain.
European Pie<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yNDYwMTQ0Ny9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTYxNTE5NDE3OX0.dPcY1tkO7nwkx6IX98Sleh7AmBpDnwlcJLfC_Z-WBlY/img.jpg?width=980" id="b35d7" class="rm-shortcode" data-rm-shortcode-id="84509a9425e13c0dd8fbe00df28a197e" data-rm-shortcode-name="rebelmouse-image" />
In this rather outlandish proposal, continental Europe's 24 cantons center on Vienna.
Image: PJ Mode Collection of Persuasive Maps, Cornell University.<p>And in 1920, an anonymous author – possibly the Austrian P.A. Maas – proposed slicing up Post-World-War-I Europe as a pie, into 24 slices that would center on Vienna's St. Stephen's Cathedral. Each of those slices would be made up of a wide and random variety of linguistic, ethnic, and religious groups – and that would be the point: the better to unite them all into one massive superstate (see also #<a href="https://bigthink.com/strange-maps/a-bizarre-peace-proposal-slice-europe-up-like-a-pie" target="_blank">851</a>).</p><p>Needless to say, both plans never left the drawing board. Would a proposal for the longitudinal and/or latitudinal redistricting of the U.S. have more traction? <br></p>
Coast-to-coast precedents<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yNDYwMTIwOS9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTY1MDM2OTE0OX0.52UjcA_YD9Y9UB9_hoSctI_xBrRDALZ2DRLkIo9a8RM/img.jpg?width=980" id="10784" class="rm-shortcode" data-rm-shortcode-id="1999808ea21e11162fdb9181c3912753" data-rm-shortcode-name="rebelmouse-image" alt="Illustration of the Connecticut Charter boundary, 1662" />
Putting the 'connect' into Connecticut: the Nutmeg State extending from the Pacific to the Atlantic.
Image: Connecticuthistory.org<p>Well, for one, coast-to-coast polities have some pedigree in America's past: some of the first colonies had claims that extended from the Atlantic all the way to the Pacific. </p><p>If history had gone entirely the way Connecticut would have wanted, the state would include such inland cities as Detroit, Chicago, and Salt Lake City, and extended to what is now the northern part of California.</p><p>Is such geopolitical weirdness reasonable or feasible today? Absolutely not. But in its randomness, would it be it as unfair as gerrymandering? </p><p><em><br></em></p><p><em>Decile maps of the contiguous United States reproduced with kind permission by u/curiouskip; found <a href="https://www.reddit.com/r/dataisbeautiful/comments/ijyn7p/oc_us_population_deciles_by_latitude_and_longitude/" target="_blank">here</a> on <a href="https://www.reddit.com/" target="_blank">Reddit</a>.<br></em></p><p><strong>Strange Maps #1054</strong></p><p><em>Got a strange map? Let me know at </em><a href="mailto:firstname.lastname@example.org">email@example.com</a><em>.</em></p>