Thales of Miletos (lived c. 625 – c. 545 BCE, with those dates being very approximate) is widely revered today with monikers such as “the first philosopher,” “the first scientist,” or “the first mathematician.” Many people today admire him, believing that he was an astounding, once-in-a-millennium kind of genius akin to Isaac Newton or Albert Einstein who single-handedly invented the idea of science as we know it. There is even a French defense contracting company named after him called the “Thales Group” (presumably because the name “Thales” makes people think of science, innovation, and progress, which are all much-needed positive associations for a company that actually makes deadly weapons that governments use to kill people).
The Thales of the modern imagination, however, is predominantly a myth. Most of the stories that people have heard about him are legends that can’t possibly be true, that are first attested many centuries after his death, or both. Much like Pythagoras of Samos and Hippokrates of Kos, the historical Thales of Miletos is an obscure figure about whom very little is known with any certainty.
Biographical and historical sources for Thales
Absolutely nothing that scholars might reasonably say was written by Thales has survived to the present day. It is highly unlikely that he ever wrote any of his teachings down at all, since none of the authors who wrote about him closest to his lifetime mention any writings attributed to him.
There were at least two treatises that were attributed to Thales in later antiquity: one titled On the Solstice and one titled On the Equinox. Both of these, however, were most likely forgeries written by someone else in Thales’s name many centuries after his death. In any case, neither of these works has survived to the present day.
As a direct result of this, everything that we know about Thales today comes exclusively from what other people wrote about him. We know that the philosopher Anaximandros of Miletos (lived c. 610 – c. 546 BCE), who is said to have been a student of Thales, did write at least one work that was known to later authors. Unfortunately, only one very tiny fragment of his work has survived. We can probably safely assume that Anaximandros wrote something about Thales, but we have no way of knowing how much he wrote about him, or what he actually said.
Most of the authors who wrote about Thales in works that have actually survived to the present day lived hundreds of years after his death. These authors knew him only from his reputation in oral folklore and from scattered mentions of him by earlier writers whose works have since been lost, probably including Anaximandros.
Thales as the “first philosopher”?
Thales’s current reputation as the “first philosopher” rests primarily on a passage that the Greek philosopher Aristotle of Stageira (lived 384 – 322 BCE) wrote in his Metaphysics 983b, which I will quote in full later in this article. In the passage, Aristotle describes Thales as “the founder of this type of philosophy,” referring to the type of pre-Socratic natural philosophy that sought to determine which fundamental element (or elements) make up the cosmos.
Centuries later, the Greek biographer Diogenes Laërtios, who most likely lived in the third century CE, begins his book The Lives and Opinions of Eminent Philosophers in book one, chapter one with an account of the life of Thales. Aristotle, Diogenes Laërtios, and other ancient Greek authors helped to establish a tradition of primacy for Thales that has become accepted in the western philosophical tradition.
Thales certainly was not the “first philosopher” ever. There are many works of ancient Egyptian and Mesopotamian literature that predate Thales by many centuries that contain what I would consider philosophical content. For instance, The Maxims of Ptahhotep, an ancient Egyptian work of didactic wisdom literature written by the vizier Ptahhotep at some point between c. 2375 and c. 2350 BCE during the reign of the pharaoh Djedkare Isesi of the Egyptian Fifth Dynasty, contains some content that I would consider philosophical.
Many other works of ancient literature, including the Epic of Gilgamesh (the standard Akkadian version of which may have been written by the Babylonian scribe Sîn-lēqi-unninni sometime between c. 1300 and c. 1000 BCE) and the Dialogue of Pessimism (which was written in Akkadian sometime shortly after 1000 BCE) also contain themes of philosophical existentialism.
Even if we limit ourselves specifically to the Greek tradition, it is still arguably dubious to consider Thales the “first philosopher.” For one thing, there are very few surviving written sources in Greek from the time before Thales and none of these sources are of the kind that would be likely to mention a person like him. There may, therefore, have been earlier figures similar to him who are simply not attested in the surviving historical sources.
Additionally, as I will discuss shortly, there is a lot of ambiguity about what exactly Thales actually taught. Most of what we know about his reputed teachings comes to us filtered through Aristotle and even later writers. This makes it hard to establish whether Thales actually taught anything that we today might consider “philosophy.” The best we can say is that Thales was a significant early figure in the history of ancient Greek philosophy and that later philosophers such as Aristotle regarded him as a philosopher.
ABOVE: Photograph from Wikimedia Commons showing Tablet Eleven of the Epic of Gilgamesh on display in the British Museum
Thales as the “first scientist”?
In the twenty-first century, people generally revere scientists far more than they revere philosophers. Since Thales is said to have done some science-y sounding things, many people have started describing him as the “first scientist,” instead of the “first philosopher,” to further enhance his prestige. For instance, an article purporting to be a biography of Thales on the rather untrustworthy-seeming website “Famous Scientists” begins with the pronouncement:
“Thales of Miletus lived in Ancient Greece. He was the first scientist in history.”
This website is not alone. An article published by the magazine Discover on 25 February 2021, titled “Who Was the First Scientist?” concludes that the first scientist was Thales. The conclusion of the article reads:
“After eons of divine intervention, of Zeus’s lightning bolts and Poseidon’s thrashing waves, Thales was the first to propose theories about the way the world works based on observation and reason — just as scientists do today. As far back as we can trace the intellectual heritage that culminated in modern science, it leads here.”
Despite all this talk of “observation and reason,” however, the popular description of Thales as “the first scientist” is, quite frankly, founded on almost nothing of the sort.
The first problem with this notion is that, as I shall address shortly, we can’t confirm that Thales actually did any of the science-y sounding things that he is said to have done. The second problem is that, even if we could confirm this and we took a loose enough definition of the word “scientist” that it could include Thales, we would also have to include all the individuals from ancient Egypt and Mesopotamia who lived before Thales who are reported to have done science-y sounding things as well.
ABOVE: Screenshot of the top of the article about Thales on the website “Famous Scientists
Predicting the eclipse
Thales’s contemporary reputation as a “scientist” rests primarily on stories portraying him as an almost miraculous prognosticator of future events. Probably the most famous story about Thales in antiquity was the story that he supposedly managed to predict a solar eclipse. The earliest version of the story is told by the ancient Greek historian Herodotos of Halikarnassos (lived c. 484 – c. 425 BCE) in his book The Histories 1.74.1–2. Herodotos writes, as translated by A. D. Godley:
“After this, since Alyattes would not give up the Skythians to Kyaxares at his demand, there was war between the Lydians and the Medes for five years; each won many victories over the other, and once they fought a battle by night. They were still warring with equal success, when it happened, at an encounter which occurred in the sixth year, that during the battle the day was suddenly turned to night. Thales of Miletos had foretold this loss of daylight to the Ionians, fixing it within the year in which the change did indeed happen.”
Now, I actually wrote an article about the eclipse of Thales all the way back in August 2017. At the time, I had just entered my senior year of high school and I was still just using my blog to tell fun and interesting stories from the ancient world that I had come across. (The title “Tales of Times Forgotten” actually made a lot more sense back then.) The article is very short, especially compared to the articles I write now, and, although I do note in the article that many historians doubt that Thales really predicted the eclipse, I don’t think that it really expresses sufficient skepticism of Herodotos’s story.
It is possible, using current astronomical knowledge, to predict the exact day and time when a solar eclipse will occur. Thales, however, certainly did not have access to astronomical information that would have allowed him to predict this. The classicist Peter Gainsford, who taught at Victoria University of Wellington up until two years ago, has written an article thoroughly debunking the idea that Thales could have accurately predicted the eclipse using the astronomical information available at the time, meaning that the interpretation of Herodotos’s story that claims that Thales accurately predicted the eclipse using genuine astronomical knowledge is untenable.
If we pay close attention to what Herodotos says, however, he doesn’t say that Thales predicted the exact date and time of the eclipse, only the year, which is much less impressive. Furthermore, Herodotos most likely wrote his Histories around a century and a half after the eclipse that Thales allegedly predicted and it is quite likely that the story changed over the course of that time to make Thales’s accomplishment seem more impressive.
It is possible that Thales may have only known that eclipses sometimes happen and, perhaps, using this very rudimentary knowledge, he may have genuinely made some kind of vague prediction, perhaps along the lines of “At some point in, I don’t know, a few years or so from now, there will be an event where day will turn into night!” Then, when an eclipse actually occurred, people became convinced that Thales had correctly predicted it, even though it was really just luck.
It is also possible that the story is entirely a legend with no historical basis whatsoever.
ABOVE: Photograph from Wikimedia Commons of a total solar eclipse taken in 1999 in France
Identifying the cause of an eclipse?
Related to the story of Thales supposedly predicting a solar eclipse are reports that he correctly identified that solar eclipses are caused by the moon passing between the earth and the sun. There are two different sources that claim this and it is unclear how they are related to each other.
Around the turn of the twentieth century, two British archaeologists named Bernard Pyne Grenfell and Arthur Surridge Hunt excavated the rubbish dump of the city of Oxyrhynchos in Egypt. In this rubbish dump, they found hundreds of thousands of fragments of ancient papyrus manuscripts dating to the Hellenistic and Roman periods.
In 1986, the scholar Michael A. Haslam published one of these papyrus texts as Papyrus Oxyrhynchus 3710. The text in question is a portion of an ancient scholarly commentary on Book Twenty of the Odyssey. The commentary is full of quotations from earlier ancient writers. In column two, lines 38–43, the commentator quotes a passage from the astronomer Aristarchos of Samos (lived c. 310 – c. 230 BCE), who, in turn, summarizes what he believed Thales had said about the cause of a solar eclipse. The quote from Aristarchos reads:
“ἔφη τε ὁ μὲν Θαλῆς ὅτι ἐκλείπειν τὸν ἥλιον σελήνης ἐπίπροσθεν αὐτῷ γενομένης, σημειούμε[νος τοὺς ὅρους] τὴς ἡμέρας ἐν ᾗ ποιεῖται τὴν ἔγλειψιν.”
This means (in my own translation):
“And Thales said that the sun is eclipsed by the moon coming in front of it and he indicated the limits of the day in which it may make the eclipse.”
You can view photos of the actual papyrus this quotation comes from on this website.
ABOVE: Detail of the lines from Papyrus Oxyrhynchus 3710, from the photo on this website, with the quotation from Aristarchos about Thales circled in red
The other testimony that Thales identified the cause of an eclipse comes from a different source. Sometime in the first or second century CE, an eclectic philosopher named Aitios wrote a work titled Concerning Opinions, which was a collection of summaries of opinions of older philosophers and quotations from philosophers’ writings that have since been lost.
Aitios’s own work has not survived, but two works based on it—one spuriously attributed to the philosopher Ploutarchos of Chaironeia (lived c. 46 – after c. 119 CE) and one written by the philosopher Ioannes Stobaios in the fifth century CE—have survived, containing abbreviated versions of Aitios’s summaries and quotations, which are numbered among the testimonia and fragments of the pre-Socratic philosophers.
One fragment from Aitios (Diels-Kranz 11 A17b = Aitos 2.27.5) claims that Thales correctly identified that the moon does not produce light of its own, but rather merely reflects the light of the sun. Another fragment (Diels-Kranz 11 A 17a = Aitios 2.24.1) claims that Thales identified the moon passing between the earth and the sun as the cause of a solar eclipse.
Unfortunately, both Aristarchos and Aitios’s testimonies are very late. Aristarchos was writing around three hundred years after Thales’s death and Aitios was writing around six hundred or seven hundred years after Thales’s death. Neither of them had access to any genuine writings of Thales himself, since Thales never wrote anything. Moreover, they were both writing long after Herodotos, they almost certainly knew Herodotos’s story about Thales predicting an eclipse, and they were writing at a time when it was widely known among educated Greeks that solar eclipses are caused by the moon passing in front of the sun.
It is entirely possible that someone somewhere along the line simply assumed, based on Herodotos’s story of Thales predicting the eclipse, that Thales must have known the cause of an eclipse in order to have predicted one. Alternatively, it is possible to imagine that Aristarchos and Aitios’s testimonies come from a common source older than Herodotos and that, somewhere along the line, stories claiming that Thales identified the cause of a solar eclipse may have been exaggerated to claim that he predicted one. I am personally inclined to believe the former of these two possibilities.
ABOVE: Photograph from Wikimedia Commons of the moon, which, according to Aitios, Thales correctly identified as reflecting the light of the sun and passing in front of the sun during a solar eclipse
Getting rich through astrology
Leaving the ancient reports about Thales and solar eclipses aside, the most famous story about Thales today is probably the story of how he supposedly amassed a fortune for himself by accurately predicting the harvest for the following year by observing the stars and other heavenly bodies. The earliest surviving retelling of this story comes from Aristotle, who tells the story in his Politics 1.4.6–18 (1,259a). Aristotle writes, as translated by H. Rackham:
“Thales, so the story goes, because of his poverty was taunted with the uselessness of philosophy; but from his knowledge of astronomy he had observed while it was still winter that there was going to be a large crop of olives, so he raised a small sum of money and paid round deposits for the whole of the olive-presses in Miletos and Chios, which he hired at a low rent as nobody was running him up; and when the season arrived, there was a sudden demand for a number of presses at the same time, and by letting them out on what terms he liked he realized a large sum of money, so proving that it is easy for philosophers to be rich if they choose, but this is not what they care about. Thales then is reported to have thus displayed his wisdom . . .”
This story is possibly more famous now than it ever was in antiquity because it appeals perfectly to both the modern love of science and the modern ideal of capitalist entrepreneurship. I’ve often seen people try to cite this story as the first example of someone proving that science has practical applications. The article published by Discover earlier this year that I quoted near the beginning of this article credulously retells this exact story as evidence that Thales was a scientist. The article reads:
“Thales lived in poverty, and the people of Miletus took this as proof of philosophy’s uselessness. To teach them otherwise, he used ‘his skill in the stars’ to foresee a great olive harvest the coming year. He then bought all the olive presses in the region and, when the harvest came, ‘let them out at any rate which he pleased, and made a quantity of money.’ Thus, Aristotle writes, ‘he showed the world that philosophers can easily be rich if they like, but that their ambition is of another sort.’”
There is, however, a major problem with this tale, which is that, quite simply, there is no way that it can possibly be true. First of all, it is impossible to predict in advance whether there will be a good or bad olive harvest in a certain year using astronomy, since harvests are dependent on complex and difficult-to-predict climatological factors, most of which have no direct connection to the motions of the heavenly bodies.
As I discuss in this article I wrote in April 2020, most people in ancient times believed in the power of astrology to predict the future and this seems to be what Aristotle is imagining here. We now, however, know that astrology is pseudoscience and it is actually useless for predicting the future.
Another reason why we should be skeptical of this story is because Aristotle is the earliest author to mention it, he was writing around two hundred years after Thales’s death, and he does not cite any earlier sources. Yet another reason to be skeptical of this story is because it too easily serves as an exemplum of the usefulness of inquiry into nature, almost as though it were made up specifically for this purpose.
The combination of these factors means that, even if it were possible to predict whether there will be a good or bad harvest in a certain year using astrology, the story would still be quite dubious.
ABOVE: Photograph taken by David Shankbone from Wikimedia Commons of an olive mill and olive press from the site of Capernaum in Israel, dating to the time of the Roman Empire
Thales the mathematician?
Today, Thales is also revered as having supposedly been a great mathematician. For instance, on 12 August 2021, I happened to stumble across a tweet by the British writer and political activist Aaron Bastani, who published a book in 2019 titled Fully Automated Luxury Communism and, at the time of the tweet, was apparently selling T-shirts that say “I am literally a communist.” Bastani’s tweet declares:
“What Thales was to mathematics, Marx was to political economy.”
This declaration is, if anything, an insult to Karl Marx. There is no solid evidence to suggest that Thales ever did any significant work in mathematics, whereas Marx is at least known for certain to have actually written significant works about political economy.
ABOVE: Screenshot of a tweet made by Aaron Bastani on 12 August 2021 about Thales and Karl Marx
Thales’s reputation as a great mathematician primarily rests on the popular belief that he was the one who discovered the theorem in elementary geometry that now bears his name. This notion, however, is highly dubious.
The first problem for the idea that Thales discovered Thales’s theorem is the fact that the Babylonians already knew about the applicability of this theorem, at least in certain cases, many centuries before Thales was even born. The second problem is that the legend that Thales discovered Thales’s theorem seems to have only developed centuries after Thales’s death.
The earliest definite attestation of the attribution of Thales’s theorem to Thales of Miletos in a source that has actually survived is in Diogenes Laërtios’s Lives and Opinions of Eminent Philosophers 1.1.24. Diogenes, in turn, cites Pamphile of Epidauros, a Greek historian who lived in the middle of the first century CE, as his source. Pamphile is a fascinating figure, since she is the only ancient female historian who wrote in the Greek language about whom there is any significant surviving information. I wrote a whole article about her in July 2021, which I highly recommend reading for those who have not read it. In any case, Diogenes Laërtios writes, as translated by R. D. Hicks:
“Pamphile states that, having learnt geometry from the Egyptians, he was the first to inscribe a right-angled triangle in a circle, whereupon he sacrificed an ox. Others tell this tale of Pythagoras, amongst them Apollodoros the arithmetician.”
The later writer Proklos the Successor (lived 412 – 485 CE), who lived about two hundred years after Diogenes, also attributes Thales’s theorem to Thales, but he cites an earlier source: the book History of Geometry, written by the historian Eudemos of Rhodes (lived c. 370 – c. 300 BCE). Proklos writes, as translated by Arthur Fairbanks et al.:
“Eudemos in the History of Geometry refers this theorem to Thales; for the method by which they say he demonstrated the distance of ships out at sea must, he says, have entailed the use of this theorem.”
Eudemos wrote around four hundred years before Pamphile and Pamphile almost certainly got the story from him, whether directly or indirectly. Eudemos is almost certainly the ultimate source of the story.
The problem is that Eudemos was writing over two hundred years after Thales’s death. Moreover, he seems to conclude that Thales must have used Thales’s theorem not because he has a source that specifically says Thales discovered the theorem and used it, but rather because he is familiar with a legend about Thales calculating the distance of ships at sea and he concludes that Thales must have used the theorem in order to do this.
It is possible that the legend Eudemos relies on is true, that Eudemos’s supposition is correct, and that Thales did use Thales’s theorem. On the other hand, it is entirely possible that Eudemos’s legend is simply another apocryphal story someone told about Thales in order to illustrate his intellect.
In any case, even if we accept the first of these options, this only entails that Thales must have known the theorem and used it; it does not in any way entail that he must have been the one who first discovered the theorem.
ABOVE: Diagram from Wikimedia Commons meant to illustrate Thales’s theorem
Measuring the pyramids
Later, in The Lives and Opinions of Eminent Philosophers 1.1.27, Diogenes Laërtios cites the Peripatetic philosopher Hieronymos of Rhodes (lived c. 290 – c. 230 BCE), who records that Thales measured the heights of the Egyptian pyramids by measuring their shadows. Diogenes writes, as translated by Hicks:
“He had no instructor, except that he went to Egypt and spent some time with the priests there. Hieronymos informs us that he measured the height of the pyramids by the shadow they cast, taking the observation at the hour when our shadow is of the same length as ourselves.”
This story is at least plausible. A person can actually measure the height of a pyramid if they measure the length of the shadow it casts at a particular time of day when the lengths of shadows are equal to the heights of the objects of which they are shadows on a certain day when the shadow is symmetrical.
Hieronymos, however, is the earliest source for this story, he was most likely writing sometime around three hundred years after Thales’s death, and, as far as we know, he was not relying on any earlier sources. Furthermore, we know that there was a tendency among Greek writers in the fourth century BCE to claim that famous Greek philosophers had studied in Egypt. (See, for instance, this article I wrote in March 2021 assessing whether Pythagoras really studied in Egypt, as many ancient writers claim he did.) Taken together, these factors make the story highly dubious.
Moreover, even if Thales actually did measure the heights of the pyramids using their shadows, all this would prove is that he was at least mildly clever and he had extremely good timing. It would not prove that he was a mathematical genius for the ages. It doesn’t take an Albert Einstein to measure the length of a shadow.
ABOVE: Photograph from Wikimedia Commons of the pyramids of Giza, which Thales is said to have measured by measuring their shadows
The historical Thales
If Thales didn’t really predict an eclipse, he didn’t really get rich using astrology, he didn’t really discover Thales’s theorem, and he probably didn’t measure the pyramids using their shadows, what exactly did he do?
Unfortunately, as I have repeatedly emphasized, the historical Thales is poorly attested. Most of our information about him comes from people who lived centuries after his death who knew him only by his reputation. That being said, the earliest sources about Thales do, at the very least, seem to reflect certain ideas that people who lived close to his lifetime believed about him.
The one thing we can say about Thales with perhaps the greatest confidence is that he was an astrologer and he had a reputation for predicting natural phenomena. Herodotos’s story about Thales predicting the eclipse and Aristotle’s story about Thales becoming wealthy by predicting the harvest for the next year are both probably apocryphal. They do, however, reflect a real reputation that Thales certainly had not too long after his death and probably had during his actual lifetime.
We can also know the philosophical views that were most closely associated with Thales in the early centuries after his death. Unfortunately, as I have already mentioned, nearly everything we know about this subject comes to us filtered through various treatises written by Aristotle.
Aristotle was writing around two hundred years after Thales’s death, Thales never wrote any of his ideas down as far as we know, meaning Aristotle couldn’t have had access to his own ideas in written form, and Aristotle doesn’t cite any earlier sources for his information about Thales’s philosophy. It is therefore very unclear where Aristotle is getting this information from. It is possible that a great deal of what he says about Thales comes simply from rumors.
Everything is water
In any case, Aristotle records in his Metaphysics 1.983b that Thales believed that water is the essential monistic substance that constitutes all things. He writes, as translated by Hugh Tredennick:
“That of which all things consist, from which they first come and into which on their destruction they are ultimately resolved, of which the essence persists although modified by its affections—this, they say, is an element and principle of existing things. Hence they believe that nothing is either generated or destroyed, since this kind of primary entity always persists.”
“Similarly we do not say that Socrates comes into being absolutely when he becomes handsome or cultured, nor that he is destroyed when he loses these qualities; because the substrate, Socrates himself, persists. In the same way nothing else is generated or destroyed; for there is some one entity (or more than one) which always persists and from which all other things are generated. All are not agreed, however, as to the number and character of these principles.”
“Thales, the founder of this school of philosophy, says the permanent entity is water (which is why he also propounded that the earth floats on water). Presumably he derived this assumption from seeing that the nutriment of everything is moist, and that heat itself is generated from moisture and depends upon it for its existence (and that from which a thing is generated is always its first principle). He derived his assumption, then, from this; and also from the fact that the seeds of everything have a moist nature, whereas water is the first principle of the nature of moist things.”
We now know that Thales was wrong and that water is not, in fact, the monistic substance that constitutes all things, but there is no way Thales could have known this in the sixth century BCE.
ABOVE: Photograph from Wikimedia Commons showing a drop of liquid water
Everything has a soul
Aristotle records in his treatise On the Soul 405a19 that Thales also believed that souls are the cause of all motion and that all things have souls, even seemingly inanimate objects, arguing that magnetic rocks must have souls because they can move iron. Aristotle writes, as translated by Walter Stanley Hett for the Loeb Classical Library:
“Thales, too, to judge from what is recorded of his views, seems to suppose that the soul is in a sense the cause of movement, since he says that a stone has a soul because it causes movement to iron.”
Later, in On the Soul 411a, Aristotle writes what is probably the most famous articulation of the view he attributes to Thales:
“Some think that the soul pervades the whole universe, whence perhaps came Thales’ view that everything is full of gods.”
In other words, according to Aristotle, Thales was a panpsychist and a pantheist. There are philosophers today who still defend these positions. I do not, however, think that any of them defend these positions using magnets, since we now know that magnetism can be explained without relying on the assumption that all things have souls. Thales’s guess about the souls, though, isn’t a bad shot, considering the time and place in which he lived.
ABOVE: Photograph from Wikimedia Commons showing a loadstone attracting pieces of iron
The earth as a flat disk that floats on water
Aristotle, writing in his On the Heavens 294a28-b1, attributes the idea that the earth is a flat surface floating on water to Thales. He immediately goes on to reject this notion, arguing that it is impossible, citing the empirical observation that earth cannot float on water. He writes, as translated by J. L. Stocks:
“Others say the earth rests upon water. This, indeed, is the oldest theory that has been preserved, and is attributed to Thales of Miletos. It was supposed to stay still because it floated like wood and other similar substances, which are so constituted as to rest upon water but not upon air. As if the same account had not to be given of the water which carries the earth as of the earth itself! It is not the nature of water, any more than of earth, to stay in midair: it must have something to rest upon.”
“Again, as air is lighter than water, so is water than earth: how then can they think that the naturally lighter substance lies below the heavier? Again, if the earth as a whole is capable of floating upon water, that must obviously be the case with any part of it. But observation shows that this is not the case. Any piece of earth goes to the bottom, the quicker the larger it is.”
I wrote an article in October 2020 debunking the popular misconception that Aristotle was an ignorant stooge who just claimed things were true because they sounded true to him without using any kind of empirical evidence or conducting any experiments. This passage is a yet another excellent example of Aristotle refuting a claim made by an earlier thinker using empirical evidence that he can only have gained through experimentation; he can’t have known that earth sinks in water without actually putting earth in water to see if it would sink.
As I discuss in this article I wrote in February 2019 debunking the misconception that people in pre-modern times all believed that the earth is flat, Aristotle ultimately comes to the correct conclusion in On the Heavens that the earth is a sphere that floats unsuspended in space. He does this based on three main observations:
- Gravity pulls all matter towards the center of the earth, which necessarily results in a planet that is roughly spherical.
- The earth always casts a circular shadow on the moon during a lunar eclipse and the only shape that always casts a circular shadow no matter which direction the light hits it from is a sphere.
- When a person travels north or south, the stars that are visible change, meaning that the surface of the earth must be curved.
This is clearly a case where, if Thales really held the view which Aristotle attributes to him, Thales was clearly wrong and Aristotle was clearly right.
ABOVE: Composite satellite image of the earth as a sphere in 2012
I’m convinced that Thales was an intelligent man who tried to explain the world around him as best as he could, relying on the information that was available to him at the time. He does not, however, seem to have been nearly as much of a colossal figure in the history of philosophy or science in general as he is often made out to have been. He was certainly not the “first philosopher” ever, probably not the “first philosopher” in the Greek tradition, and certainly not the “first scientist” or the “first mathematician” in any sense.