actually not really how nature works the way nature works is that if there is a state that state causes the readings so this model here is really the causal model that we have available given a state it will cause a distribution over readings and when you build a sensor and you try to sell to people this is your sensor model that you would provide it said this is the distribution of our outcomes given this situation this is fishing-rod come given this other situation and so forth for example for a laser range file you might say well if