The probability that something happens, in a vacuum, is pretty meaningless. It's just a number that changes based on evidence you have. For example, if you knew

The probability that something happens, in a vacuum, is pretty meaningless. It's just a number that changes based on evidence you have. For example, if you knew nothing at all about the universe, the probability that the sun would go up tomorrow could be extremely low. The probability of the sun going up tomorrow given our knowledge of the world is much more meaningful. A perfect example of how this is significant is the very first assumption: while your dad may have met 20,000 women, the probability that he would date and then marry your mother given his qualities and preferences in women is most likely much higher than 1/20,000. Another example: let's say we have a loaded die. If we don't know anything about it, the probability of getting a 6 is 1/6. If we know it's loaded, the probability is something else. Which value is correct? If it's the latter, then wouldn't the probability of your being born really be something like the probability of your being born given a bunch of environmental factors and the like? Basically, the number presented here is mostly devoid of value. That said, the visualization is very good and gets its point across both succinctly and clearly.