logical -- (capable of or reflecting the capability for correct and valid reasoning; "a logical mind")
legitimate, logical -- (based on known statements or events or conditions; "rain was a logical expectation, given the time of year")
coherent, consistent, logical, ordered -- (marked by an orderly, logical, and aesthetically consistent relation of parts; "a coherent argument")
coherent, logical, lucid -- (capable of thinking and expressing yourself in a clear and consistent manner; "a lucid thinker"; "she was more coherent than she had been just after the accident")
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