sentient: responsive to or conscious of sense impressions <sentient beings>
sapient: possessing or expressing great sagacity
sagacious: a ) of keen and farsighted penetration and judgment: discerning <sagacious judge of character>; b) caused by or indicating acute discernment <sagacious purchase of stock>
— Webster’s Dictionary
One could say that a sentient being responds to sense impressions, and a sapient being is capable of reason.