First off, this question was inspired by the following Facebook post:
“So since 50,000 years human haven’t evolved into anything different … yet [scientists] believe in Darwin theory that man evolved from apes and that doesn’t add up.”
This faulty argument is full of logical fallacies. Before we explain why it’s not even a valid argument, let’s tackle the facts.
First, while 50,000 years is not a long time in evolutionary terms, we do observe significant evolutionary changes in humans over this period. For example, we’ve seen the evolution of various skin, hair, and eye colors, as well as facial features and different shaped ears. These adaptations are responses to different environmental pressures and genetic drift as humans spread across diverse climates and geographies. To deny what we are seeing in real-time is to deny reality.
Second, the 50,000-year mark is particularly significant for the evolution of the human brain’s raw cognitive abilities. By this point, our brains had largely settled at their current level of complexity and capability. This does not mean that evolution has stopped. Human brains may stay this way for millions of years, or they may evolve significantly over the next few millennia.
Finally, the original faulty argument is both an “argument from ignorance” and a “false equivalence.” An argument from ignorance is when someone concludes that because they personally find something difficult to understand or believe, it must not be true. It is also a false equivalence, where the skeptic equates the relatively short period of 50,000 years with the much longer timescales required for significant evolutionary changes.