Chemisor writes: We often hear this disconnect in the climate debate: sceptic Joe says "human impacts are small and likely not harmful"; alarmist Arthur says "humans are affecting the climate, therefore we must act now". It is not possible to get the alarmist to answer the claim of the skeptic that the impacts are likely to be small. I believe the disconnect results because the alarmist is using categorical thinking. In this mode, if something is bad, it is bad. Water is either clean or not clean. Forest is either wilderness or it is defiled. This conversation cannot progress because the world views of the sceptic and the alarmist are incompatible. The words they use do not mean the same thing.