claim: Through decades of research, it has become clear that human civilization, roughly 6,000 years old, developed during an unusually stable period for global sea levels.
evidence: Assuming a fair coin: The probability of 20 heads, then 1 tail is 0.520 × 0.5 = 0.521 The probability of 20 heads, then 1 head is 0.520 × 0.5 = 0.521 The probability of getting 20 heads then 1 tail, and the probability of getting 20 heads then another head are both 1 in 2,097,152.