The document discusses how Charles Darwin and Sigmund Freud challenged Enlightenment ideas about human development and progress through their discoveries during the Intellectual Revolution. Darwin published his theory of evolution by natural selection in Origin of Species, which contradicted the idea that humans were in control of change. Freud founded psychoanalysis and argued that the human brain develops unconsciously in ways not always rational, challenging the view that humans are fully rational. Their discoveries forced a reexamination of humanity's role and provided the basis for today's scientific outlook.

1. Delaney Caballero<br />Mr. Smith<br />AP European History<br />25 January 2011<br />The Challenge of Human Development and Progress<br />The revolution in intellectual history that forced educated men to take a new look at the universe and man’s role in it was the Intellectual Revolution. Previously accepted ideas were doubted, and many of them had to be replaced. The development of modern science was the basis for the Intellectual Revolution. The discoveries of Charles Darwin and Sigmund Freud are the origin for today’s scientific outlook. The many discoveries of Charles Darwin and Sigmund Freud challenged the Enlightenment Ideas about human development and progress. <br />Charles Darwin was one of the most controversial men in the Intellectual Revolution and throughout history today. With Darwin’s Origin of the Species, the Intellectual Revolution smashed the self- satisfied world of Victorian England. The book was very controversial because he scientifically formulated and proved his theory of evolution based on natural selection. Darwin’s theory of evolution stated that all existing forms of life have descended from earlier and simpler forms and that the principal means of evolution was by natural selection, or survival of the fittest. In The Decent of Man, Darwin dealt with the evolution of mankind. He argued that humans share a common ancestry with primates because of the opposable thumb. Darwin’s theories challenged Enlightenment ideas and theories because the Enlightenment thinkers believed that people were in charge of change and natural selection does not benefit everyone. <br />Another of the most important controversial men in the Intellectual Revolution was Sigmund Freud. Freud was an Austrian physician that became the founder of psychoanalysis and modern psychiatry. Freud believed that the brain evolved over time throughout the development of the human being. He thought that the brain developed as much as the physical body and argued that boy’s and girl’s brains developed differently. Freud stressed the idea that there is a conscious and unconscious brain and that the unconscious brain is the key to knowing the inner nature of man. The most controversial of Freud’s concepts was that of homosexuality. He described homosexuality as a brain dysfunction and stated that there is a strong attachment top the parent of the opposite sex and hostility to the other parent. The Enlightenment theories and ides about human development and progress was challenged by Freud because Freud argued that human being are not fully in control of their brains and our brains do not always work in rational ways. <br />The Intellectual Revolution forced educated men to take a new look at the universe and man’s role in it. The basis for the Intellectual Revolution was the development of modern science. The discoveries and ideas of Charles Darwin and Sigmund Freud are the origin for today’s scientific outlook. Their many discoveries challenged the Enlightenment view on human development and progress. <br />