The world is an equation?

It's a classic thought: the entire world can be explained by numbers and equations. So it's nice to have the feeling that there are some things that are a bit more chaotic and unpredictable. Like love. However, there are people that claim that even this can be calculated. Dr. John Gottman, for instance. In his "Love Lab", he can predict the success or failure of a marriage within 15 minutes. And, what's more important: with 85% percent accuracy, he claims. It's a bit like weather-forecasting: it makes the prediction more accurate, but you still cannot tell the exact future. The mathematics behind it is completely beyond me, but it's still a fascinating idea.
Some years ago, Jordan Ellenberg wrote an article about this mathematical love in Slate magazine, called "Love by the Numbers".