[AP 1989] Which of the following had the LEAST effect on European thought in the first half of the 20th century?

a. the uncertain and complex universe of Einstein's and Heisenberg's physics

b. the undermining of the optimistic belief in human rationality by Freudian psychology

c. the utopian literature of Sir Thomas More and Roger Bacon

d. logical empiricism's limitation of the scope of philosophical inquiry to the scientifically and mathematically verifiable

e. the Darwinist idea of human behavior as determined by evolutionary forces

To determine which option had the LEAST effect on European thought in the first half of the 20th century, we need to evaluate the impact of each option and compare them.

a. the uncertain and complex universe of Einstein's and Heisenberg's physics: This option introduced major paradigm shifts in the understanding of the physical world, challenging established scientific concepts and leading to new theories like relativity and quantum mechanics. It had a significant impact on European thought, as it redefined the notions of space, time, and causality.

b. the undermining of the optimistic belief in human rationality by Freudian psychology: Freudian psychology introduced ideas about the unconscious mind, psychoanalysis, and the influence of complex psychological processes on human behavior. This challenged the belief in human rationality and had a substantial impact on European thought, especially in fields like psychology, literature, and art.

c. the utopian literature of Sir Thomas More and Roger Bacon: Utopian literature, while influential in its own right, had a relatively limited impact on European thought in the first half of the 20th century. It did not bring about significant paradigm shifts or transformative ideas in the same way as the other options.

d. logical empiricism's limitation of the scope of philosophical inquiry to the scientifically and mathematically verifiable: Logical empiricism, also known as logical positivism, emerged as a dominant philosophy in the early 20th century. It proposed that meaningful knowledge could only be derived from scientifically or mathematically verifiable statements. This limitation had a substantial impact on European thought, as it influenced various disciplines, including philosophy, science, and social sciences.

e. the Darwinist idea of human behavior as determined by evolutionary forces: Darwin's theory of evolution by natural selection had a profound influence on European thought, challenging traditional religious or deterministic views of human behavior. It provided a scientific explanation for the development of species, including humans. This idea deeply impacted fields such as biology, anthropology, and sociology, reshaping European thought about human origins and behavior.

Based on the evaluation, the option that had the LEAST effect on European thought in the first half of the 20th century is c. the utopian literature of Sir Thomas More and Roger Bacon. While it was influential during its time, its impact was not as wide-ranging or transformative as the other options presented.