According to the best current archaeological evidence, until around 50,000 years ago, the human race, modern Homo sapiens, was confined to a small region surrounding the Rift Valley in eastern Africa. The climate was favorable, the game was fairly abundant, and nontechnological humans were more than adequate for the challenge of the environment. As a result, the Rift Valley dwellers were able to get by with a tool kit limited to a little more than the same split-rock hand axes that had served their Homo erectus ancestors for the previous million years. For some unknown reason, however, a few bands of these people decided to leave this relative paradise and travel north to colonize Europe and Asia, eventually going on from there to cross the land bridge into the Americas.
They went north, into the teeth of the Ice Age, into direct competition with giant carnivores and stocky Neanderthals who had already adapted to life in the cold. They went north, into a world of challenge, where fruit, vegetables, and game were not available all year long and where efficient weapons, clothing, and housing were necessary. In abandoning Africa, they embraced a wider world that could be survived only through the development of technology. Thus was born Homo technologicus, man the inventor, amid ice and fire. Thus humanity transformed itself from an East African curiosity to the dominant species on this planet.
In a sense, the biblical tale of Genesis tells this story but has it backward. It was not eating of the Tree of Knowledge that forced humankind to leave Paradise. Rather, it was the abandonment of Paradise that forced humanity to seek the forbidden fruit.
Back in the Sputnik era, the Russian space visionary Nikolai S. Kardashev outlined a three-tier schema for classifying civilizations. Adopting Kardashev’s scheme in slightly altered form, I define a Type I civilization as one that has achieved full mastery of all its planet’s resources. A Type II civilization is one that has mastered its solar system, while a Type III civilization would be one that has access to the full potential of its galaxy. The trek out of Africa was humanity’s key step in setting itself on the path toward achieving the mature Type I status that the human race now approaches.
The challenge today is to move on to Type II. Indeed, the establishment of a true spacefaring civilization represents a change in human status as fully profound - both as formidable and as pregnant with promise - as humanity’s move from the Rift Valley to its current global society.
Space today seems inhospitable and as worthless as the wintry wastes of the north might have appeared to an average resident of East Africa 50,000 years ago. But yet, like the north, it is the frontier whose possibilities and challenges will allow and drive human society to make its next great positive transformation.
Exploring Space: Creating A Spacefaring Civilization | Robert Zubrin
This. Exactly my argument to those who are against space exploration.