Sentence:  But each man's understanding, such as it is, must be his guide; and he, who has not courage to make a free use of it, but obtrudes the opinions of others, <WSD>unsifted</WSD> and unexamined, on his readers, betrays more want of respect for their understanding, than diffidence of his own. 
Meaning of the word marked with <WSD> tags:  Inexperienced; untried, unscrutinized.