Humans, a recent arrival on the planet Earth, appear to be on track to vanish in a few 100 years. According to a recent article in Lancet (1), population growth is slowing and the aggregate population is expected to peak in 40 years or so, just under 10 billion. With a Total Fertility Rate well under the replacement rate in many countries and the rest moving rapidly in that direction, humans are on course to a slow and painful extinction in the blink of an eye. In less than a century, the value of a human could rise to such levels that countries may fight for them or devise ways to manufacture them.
Humans were never expected to be here. A mere 75,000 years ago they were reduced to a few thousand samples during the Toba catastrophe (2). As they ventured out of Africa, just 50,000 years ago, they were given a palette of relative freedom to create their own history. They eliminated any other humanoid they found systematically, including the Neanderthals and Denisovans, albeit after mating with them, using abundant experience from clan-based violence borrowed from their ancestors (3). In less than 10,000 years ago, when humans settled and succumbed to agriculture and domestic animals, they exposed themselves to organisms that could wipe them out quickly. Their height and health started to decline since then (4) and with little knowledge of their invisible enemies, they remain to be sitting ducks in the midst of advancing pandemics.
There are three common themes that characterize Homo-sapiens all through their sojourn on the blue planet that possesses an incredible level of homeostasis. First, they are driven by a simple objective function, just like any other biological entity on Earth, a need for energy and a desire to perpetuate their architecture — more specifically, food and sex. Second, they try to maximize this objective function through violence, perhaps worse than other animals that have shown to be prone to irrational empathy. A freak evolutionary quirk ballooned their brains and that gave them the ability to strategize and collaborate to eliminate the foe. Ironically, the bigger brain accelerates their path to extinction as they devise weapons of mass destruction, religions, and caste systems. Finally, their long-practiced clan behavior pushes them to segment to ever so finer distinctions based on visible surface features and presumed differences. In other words, the deadly cocktail of food, sex, violence, and racism has set them up for the final assault by disease as their numbers naturally decline due to falling fertility rates.
Physics is yet to provide a reasonable explanation of life. The most elegant of ideas has been the second law of thermodynamics (5) and a systemic force toward increasing entropy at an ever-faster rate. Life certainly fits this as a biological organism is able to accelerate entropy by many orders of magnitude higher compared to a random combination of chemicals that make life. If so, it makes sense that Humans, an extreme form of entropy enhancing mechanisms, materialized. If the Physics holds true, they will be replaced by other forms that are more efficient in increasing entropies. The new species has to be more potent than humans in the current environment. Recent advancements in Artificial Intelligence and Robotics may fit the bill. It is more likely that the environment of contemporary life will be blown to pieces in a shock and awe process of massive entropy accretion.
Humans, the vanishing species, a quirky experiment of evolution, never had the staying power.