- 2025年10月19日
What is Humanity: The True Story Sleeping on the Seafloor
What is Humanity: The True Story Sleeping on the Seafloor
Prologue: The Lost Main Stage
The human history we read may be an abridged version, missing its “main stage” which now lies submerged beneath the sea.
The core of this essay rests on the following three perspectives:
- The main stage of human activity during the Ice Age was on the coastal plains that sank with rising sea levels (now the seabed). Therefore, terrestrial archaeological records are inherently biased.
- Human migration was not a one-way “Great Journey” but a dynamic, multi-directional flow, oscillating in response to climate change.
- The advancement of underwater archaeology will trigger a paradigm shift, fundamentally rewriting our understanding of human history.
Just as the image of dinosaurs transformed from “giant reptiles” to “feathered ancestors of birds,” the story of our own ancestors awaits its moment to emerge, in a completely new form, from beneath the waves.
Chapter 1: Correctly Understanding the World of the Ice Age
First, we must correctly understand the environment of the “Last Glacial Period,” the stage upon which our story unfolds.
| Term | Period (Approx.) | Characteristics |
| Last Glacial Period | 115,000 – 11,700 years ago | The last ice age when the entire planet cooled. |
| Last Glacial Maximum (LGM) | 26,500 – 19,000 years ago | The coldest peak of the Last Glacial Period, when sea levels dropped by up to 120 meters. |
| Interstadial | Cycles of several thousand years | A temporary warm period within the Ice Age. |
| Stadial | Cycles of several thousand years | An especially cold period within the Ice Age. |
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The crucial point is that the Ice Age was not uniformly frigid. It was punctuated by waves of warming (interstadials) and cooling (stadials) over thousands of years, causing the most habitable places for humanity to constantly shift.
Chapter 2: The Most Important Things Are, Truly, in the Sea
The Lost Continents
During the Last Glacial Maximum (LGM), the sea level was over 120 meters lower than it is today. This exposed vast areas of the continental shelf as dry land.
- Sundaland: A massive landmass that connected the islands of Southeast Asia to the mainland.
- Doggerland: A fertile plain in the North Sea that connected Great Britain to continental Europe.
It is highly probable that these regions, with their rivers and abundant flora and fauna, were the most desirable “prime real estate” for humankind. The terrestrial sites we find today may be nothing more than the traces of settlements in the “highlands” or “fringes” of that vast, lost world.
Reversing Common Sense
The image of the Ice Age as a “cold and miserable” time is a view biased toward high-latitude regions. In the low and mid-latitudes, the situation was completely different.
- The Green Sahara: What is now the Sahara Desert was, at times, a lush savanna with extensive lakes and rivers (the African Humid Period).
- A C Milder Climate: Even during the LGM, the temperature drop in the low to mid-latitudes was only about 5.8°C on average. It’s even possible that the climate was more pleasant than the scorching heat of today’s tropics.
Therefore, we should reframe the Ice Age not as an “era of hardship” for humanity, but rather as an “era when a vast and rich living space, much larger than today’s, was available.”
Chapter 3: Humanity Was Constantly “Coming and Going”
The narrative of the “Great Journey” from Africa to the rest of the world is an oversimplification. Human movement was far more dynamic and bidirectional.
The Climate Pendulum
The repeated cycle of stadials (cooling) and interstadials (warming) caused the habitable zones for humans to shift periodically.
- During warm periods, populations expanded from south to north and from coastal areas to the interior.
- During cold periods, populations contracted back from north to south and from the interior to warmer coastal refuges.
Rather than a linear progression, it is more natural to think of human dispersal as a pendulum-like oscillation, with populations moving back and forth between north and south, and east and west, for tens of thousands of years.
The Scale of Time
We cannot intuitively grasp a span of “50,000 years.” The arrows on migration maps, showing “humans reached Point X, Y years ago,” compress thousands of years into a single point in space. If a generation was 15 to 20 years, then 50,000 years saw more than 2,500 generations. It was a matter of course for humanity to make countless round trips, riding the waves of climate change, during that immense period.
Chapter 4: The True Meaning of the Remaining Ruins
So, what is the significance of the sites we have found, like Göbekli Tepe in Turkey or the countless Jomon sites in Japan?
These are not “out-of-place artifacts,” but rather incredibly precious evidence left on the “fringes” of a lost world.
- Why Are They There?: Places like the Japanese archipelago or the island of Java are, topographically, the “mountain ridges” of sunken continents that remained above water after sea levels rose. This is precisely why traces were more likely to survive there.
- Preserved Because They Were “Peripheral”: Cultural centers are often overwritten by new cultures in later eras. In contrast, peripheral areas or refuges are where older cultures are more easily preserved.
The “civilizations” that emerged after the agricultural revolution did not start from scratch. They may have been a form of “palimpsest,” written over a foundation of inherited cultures and technologies—including advanced seafaring skills—that had been cultivated during the Ice Age and were likely far more sophisticated than we can imagine.
Conclusion: The Humility to Know History
The strength of modern science lies in positivism. Its weakness, however, is the tendency to assume that what lacks evidence does not exist.
Ludwig Wittgenstein said, “Whereof one cannot speak, thereof one must be silent.” In human history, the parts submerged beneath the sea are precisely those things “whereof we cannot speak.” We must be humble in the face of what we do not know.
History is not a single, fixed narrative. As Foucault suggested, it is constantly being rewritten depending on the era and perspective. Today, we have acquired a new pen called underwater archaeology. We are standing at the threshold of a magnificent era, one in which we will finally add the lost chapters to the grand story of humanity.