A person who follows the philosophy of rationalism.(noun)
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Use "rationalist" in a sentence
"What seems to go hand-in-hand with this definition of SF as profoundly rationalist is the application of an oppositional definition as regards Fantasy."
"This led them to adopt the intellectualist thesis, or what we would call the rationalist thesis, regarding the mind's perception of metaphysical essences."
"What disturbs the so-called rationalist in the mystic's attitude is his propensity to see mysteries where there are none and to fail to see those that we cannot possibly escape."