Today, as you may know, is the birthday of both Brent Mydland and Jeff Chimenti. Enthusiasts being given to flights of a metafantastical nature, and the occasional occultishness, this has been seen as Meaningful. Maaaaaan. There is, of course, no deeper meaning to any Grateful Dead’s birthdays: they were born when they were born. (Except for Mickey. His birthday is Meaningful.)
But neither is this synchronicity strictly serendipity: it is no coincidence that there are two Grateful Deads with the same birthday. It is math.
To calculate the odds of two people in a group having the same birthday, you have to kinda work backwards a little. There’s 365 days in a year (let’s not bring Leap Year babies into this), so the probability of two people not having the same birth date is 364/365, which works out to better than 99%. Introduce another person, and the odds are 363/365, which you multiply by the first fraction. This makes your chances better, and because multiplication is magic, your odds hit even money very quickly: you don’t have to get too many people in a room before two will have the same birthday. It’s math.
There are two Grateful Deads with the same birthday because there have been so many Grateful Deads. Although, the fact that they’re both keyboardists is fuckin’ spooky, man.