Psychologist William James
William James was born in 1842 and the works that followed up with his age and education lead him to be regarded as the founder of American Psychology. William James began his psychology career after completing his education in medicine as a physician and the gradual interest in laboratory science lead him to becoming an elemental person in psychology. William James is famously known to contribute to pragmatism and functionalism theories in psychology. These theories among others are developed under the book he wrote on The Principles of Psychology.
He wrote The Principles of Psychology book as a large volume that was published in two parts and had approximately 1200 pages. In the volume 1 part, James attempts to describe the mental activity of the human brain by interlinking the brain activity to biological principles. In volume 2, James progresses his explanation on cognitive functions in the attempt to lay the foundational importance of the human reasoning and perception tendencies. In the book, he comes up with two important elements in psychology and they include the theory of pragmatism and functionalism. James explains pragmatism to hold on the concepts of value of ideas and usefulness of those ideas in the practical world; he believed that both are essential. Further on, he explains functionalism to as the way human beings process and internalize information leading to consciousness.
William James worked with other psychologists like Carle Lange and developed the James-Lange theory of emotion. This theory has become profound in explaining emotions as physiological reactions. He also helped develop theories like the free will theory, the epistemological theory and he also brought in new insights into the theory of evolution by analyzing mutations and what he termed as extraordinary mutations. William James contribution to psychology still has an effect to the current psychology as he developed arguments that are still in play up to date.