Logic is badly described as investigating the laws of thought. Logic seeks to discover how thoughts, in the sense of the combination of propositions held at one time, must be structured, if they are to conform to the demands of consistency. It does not deal with the diachronic processes whereby one thought succeeds another. The laws of thought in this sense are not known and neither is it known that there should be any such laws, not because the mind is a sphere of chaos, but because mental descriptions may not be apt for embedding in laws. See anomalous monism.