So an engineer, a physicist, and a mathematician move in to a new place together. Their first night, a fire starts in the house. The engineer wakes up, sees it

So an engineer, a physicist, and a mathematician move in to a new place together. Their first night, a fire starts in the house. The engineer wakes up, sees it, douses it in buckets of water, puts it out, and goes to sleep. The second night, another fire starts. This time, the physicist wakes up, sees it, calculates exactly how much water to use to put out the fire, pours exactly that much water on the fire (plus or minus experimental margin of error), puts it out, and goes to sleep. The third night they decide to search for fires before bed. The engineer does a quick sweep of the house, convinces themself there are no fires, and goes to sleep. The physicist searches a while longer, convinces themself there are no fires, goes to sleep. The mathematician searches and searches, but can't prove there are no fires, and so can't go to sleep. After some thought, they set their own fire and go to sleep, thus reducing it to an already solved problem!