<Li> Failure to question research findings that agree with prevailing political and philosophical ideology represents one of the effects of the zeitgeist . </Li> <Li> The zeitgeist does not always have negative effects . It can stimulate new ideas and creative solutions to problems . An example is seen in the different models and metaphors chosen to describe behavior and consciousness . </Li> <Li> Charles Darwin's proposition that evolution occurs by natural selection has been cited as a case of the zeitgeist, since his contemporary, Alfred Russel Wallace, was outlining similar models to Darwin during the same period (ideas that were jointly presented to the public). This view is disputed, however, by accounts that emphasize the relative simplicity of Wallace's model, and which highlight a supposed novelty within Darwin's likewise simplistic contribution . </Li> <Li> The zeitgeist of the 1920s revolved around logical positivism . Due to this, the great men of that time were able to impact psychology, such as Watson, Tolman, and Guthrie . This is important because their work on behavioral psychology was able to work against eugenics . Before this time behavioral psychology was not able to impact the field since it did not fit with the spirit of the times . For example, Twitmyer Edwin B. Twitmyer wrote a paper on the patellar reflex in 1902, but it came too early to have the impact it deserved . </Li>

Who defined philosophy as the spirit of age