Before Darwin’s finches or Dawkins’s selfish genes, there was Malthus’s unsettling discovery about population growth. As a mathematician and economist in the late 1700s, he noticed something that seems obvious now but was revolutionary then: populations grow exponentially, but food production only grows linearly.
Think about rabbits. Each pair can produce six babies per year. Next year, those six can each pair up to produce six more. In just five years, one pair could theoretically become thousands. This is exponential growth – like compound interest, but with living things.
Now think about farmland. You can only expand fields in two dimensions. Double your acreage, double your crops. Triple it, triple your crops. This is linear growth – straight-line math, no compounding.
Here’s where Malthus’s genius came in: He realized these two patterns – exponential population growth versus linear resource growth – would inevitably clash. No matter how much food we produce, population growth will eventually outpace it. Something has to give.
This insight would later revolutionize biology in ways Malthus never imagined. If populations always produce more offspring than can survive, then there must be competition. Some individuals survive while others don’t. This was the missing piece Darwin needed to understand natural selection, and Dawkins would later build on both ideas.
Malthus showed why competition was inevitable. Darwin showed how this competition led to evolution by natural selection through random adaptation. Dawkins revealed that genes themselves were the players in this competitive game, using organisms as their vehicles.
What started as Malthus’s simple mathematical observation – that two different types of growth were on a collision course – became the foundation for understanding how all life evolves. It shows how a single insight about numbers could unlock nature’s deepest patterns.
Malthus wasn’t trying to explain evolution. He was worried about human population growth and poverty. But his clear-eyed look at mathematical reality helped others see the broader pattern: Resources are always limited, populations always grow, and this dynamic tension shapes all life on Earth.