How Many Holes Does the Human Body Really Have? It Depends How You Define a Hole
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the human body, a marvel of biological engineering, presents a deceptively simple question: how many holes does it have? While a quick count of visible openings might seem straightforward, the answer quickly unravels when considering the nuances of what actually constitutes a hole – a question that even perplexes mathematicians.
beyond Simple openings: The Topological Challenge
The initial impulse is to list the obvious: mouths, nostrils, ears, and so on. But experts quickly point out that a simple tally misses a crucial distinction. Mathematicians aren’t interested in superficial openings; they require a “through hole” – a passage that connects one side of an object to the other. As mathematician William Steckles explains, a dimple or indentation isn’t a hole in the mathematical sense, even if it appears to be from our perspective.”This isn’t a true hole, as it has an end,” Steckles clarifies. Similarly, mathematical communicator James Arthur emphasizes that, in the field of topology, a hole must be a “through hole” – something you can physically pass an object through.
The Straw and the Doughnut: A Topological Equivalence
this distinction is highlighted by the classic riddle of the straw. Responses vary wildly – one hole, two holes, even zero. This discrepancy stems from our everyday understanding versus the rigorous framework of topology. Topology, it turns out, isn’t concerned with shape, but with basic properties and connections.
To illustrate, imagine molding a straw out of play dough and slowly compressing it until it resembles a doughnut. Mathematicians would argue that the straw and the doughnut are “homeomorphic” – topologically equivalent. “The hole in a straw goes all the way through it, and the opening at the other end is just the back of that same hole,” Steckles notes. A bagel, basketball hoop, or even a pretzel share this same topological property.
Counting Holes in the Human Body: A String Test
Applying this topological definition to the human body requires a more discerning approach.A simple listing of openings – mouths, urethras, anuses, nostrils, ears, milk ducts, and vaginas – isn’t sufficient. Furthermore,the body contains four less-obvious openings: the lacrimal puncta in the corners of our eyelids,which drain tears,and countless pores across the skin. But do these all qualify as “holes”?
The key, experts say, is whether a string, approximately 60 microns in width, could pass entirely through an opening. Pores, for example, while numerous, fail this test. “They’re not actually holes in the topological sense, as they don’t go all the way through,” Steckles explains. “They’re just blind pits.” Similarly, milk ducts, urethras, and even ear canals are disqualified due to their lack of complete passage.
this leaves us with a more manageable list: mouths, anuses, nostrils, and the eight lacrimal puncta (two in each eye). Though, even this count isn’t straightforward. “When the holes that pass through a shape connect together inside the shape,it makes it harder to count how many there are,” Steckles cautions,using the example of underwear – three openings,but only two holes when flattened.
The Final Tally: Seven or Eight?
following this logic, the human body appears to have seven holes. Though, a final consideration complicates matters: the female reproductive system. While often considered a blind hole, the vagina connects to the uterus and then to the fallopian tubes, which open into the peritoneal cavity. As eggs can travel between the fallopian tubes, a string could theoretically pass completely through this system.
Therefore, the mathematician’s answer is that humans have either seven or eight holes. Ultimately,the question isn’t about a simple count,but about understanding the fundamental connections within a complex system. Topologically speaking, our bodies are less like Swiss cheese and more like a carefully constructed onesie for an octopus.
