Sentence:  Eysenck (1952) was just beginning to seriously question the validity of dynamically oriented therapy, but he was a lone <WSD>voice in the wilderness</WSD> at that time. Not until the sixties did opposing points of view . . . begin to gain prominence. 
Meaning of the word marked with <WSD> tags:  A person, publication, or other source of assertions that expresses an opinion, doctrine, or point of view which is ignored or rejected by almost all others; the actual utterance of an unpopular opinion, doctrine, or point of view.