>Does no rain implies streets are dry? It would, if the only thing that could make the streets wet is rain; ie if we were in a limited model where that was tru

>Does no rain implies streets are dry? It would, if the only thing that could make the streets wet is rain; ie if we were in a limited model where that was true. We're talking in the context of a limited model in this thread. My point was that the statements are equivalent in this model. Alternatively: Imagine we were talking about the size of a pizza and how big a dinner it will lead to. A blog says "wider diameter pizzas generally lead to bigger meals. Narrower diameter pizzas generally lead to smaller meals". The first comment here says "just because wider pizzas implies bigger means doesn't mean narrower pizzas implies smaller meals, the blog has made a logical error!". I reply "in the context of roughly round pizzas the two statements are the same". You then give the example about the rain and streets. Hopefully it's clear that your general logical point isn't relevant to the pizza discussion, where there is a relationship between width and area. Similarly, in the Lindy model, which we are actually discussing, there is a relationship between age and expected lifetime. That relationship is more complex than the pizza one, which confuses things, but hopefully the pizza example makes it clear why there isn't a general logical error here.