The author borrows Heisenberg's term pertaining to the fact that the observer influences what is observed. He argues against Freud's determinism although he could have quoted Freud's doubts about determinism and his statement that if an observer is added to analysis it is no longer analysis. Instead he quotes K. Lewin, Buber, and Finch that our knowledge of man is probable, not certain or determined. Freud might have been able to agree with this in his remarks about the artist. Despite the author's views, determinism is still clinically useful even though it seems to resemble 'medieval theology'.