sentient: responsive to or conscious of sense impressions <sentient beings>  

sapient: possessing or expressing great sagacity

sagacious: a ) of keen and farsighted penetration and judgmentdiscerning <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.