In philosophy, rationality is the exercise of reason.^{[citation needed]} It is the manner in which people derive conclusions when considering things deliberately. It refers to the conformity of one's beliefs with one's reasons to believe, or with one's actions with one's reasons for action. However, the term "rationality" tends to be used differently in different disciplines, including specialized discussions of economics, sociology, psychology and political science. A rational decision is one that is not just reasoned, but is also optimal for achieving a goal or solving a problem.

Determining optimality for rational behavior requires a quantifiable formulation of the problem, and the making of several key assumptions. When the goal or problem involves making a decision, rationality factors in how much information is available (e.g. complete or incomplete knowledge). Collectively, the formulation and background assumptions are the model within which rationality applies. Illustrating the relativity of rationality: if one accepts a model in which benefiting oneself is optimal, then rationality is equated with behavior that is self-interested to the point of being selfish; whereas if one accepts a model in which benefiting the group is optimal, then purely selfish behavior is deemed irrational. It is thus meaningless to assert rationality without also specifying the background model assumptions describing how the problem is framed and formulated.

Gerd Gigerenzer (born September 3, 1947, Wallersdorf) is a German psychologist who has studied the use of bounded rationality and heuristics in decision making, especially in medicine. A critic of the work of Daniel Kahneman and Amos Tversky, he argues that heuristics should not lead us to conceive of human thinking as riddled with irrational cognitive biases, but rather to conceive rationality as an adaptive tool that is not identical to the rules of formal logic or the probability calculus.

With Daniel Goldstein he first theorized the recognition heuristic.

He has written several books on the subject of heuristics and decision making, including Simple Heuristics That Make Us Smart (1999), and Bounded Rationality: The Adaptive Toolbox (2001) with Reinhard Selten. His two books for a lay audience, Reckoning with Risk: Learning to Live with Uncertainty (2002, published in the U.S. as Calculated Risks: How to Know When Numbers Deceive You), and Gut Feelings: The Intelligence of the Unconscious (2007), have been translated into 18 languages. "Rationality for Mortals", his most recent book, investigates decisions under limited time and information. He has trained U.S. Federal Judges, German physicians, and top managers in decision making and understanding risks and uncertainties.

Peter John Kreeft (born 1937) is a professor of philosophy at Boston College and The King's College. He is the author of numerous books as well as a popular writer of Christian philosophy, theology and apologetics. He also formulated, together with Ronald K. Tacelli, SJ, "Twenty Arguments for the Existence of God".

Kreeft took his A.B. at Calvin College (1959), and an M.A. at Fordham University (1961). In the same university he completed his doctoral studies in 1965. He briefly did post graduate studies at Yale University.

Kreeft has received several honors for achievements in philosophical reasoning. They include the following: Woodrow Wilson, Yale-Sterling Fellowship, Newman Alumni Scholarship, Danforth Asian Religions Fellowship, and Weathersfield Homeland Foundation Fellowship.

He joined the Philosophy faculty of the Department of Philosophy of Boston College in 1965. His intellectual reputation stems from his strengths in debating and summarizing the philosophical arguments of the major Western philosophers. He has debated several academics in issues related to God's existence. Shortly after he began teaching at Boston College he was challenged to a debate on the existence of God between himself and Paul Breines, an atheist history professor, which was attended by a majority of undergraduate students. Kreeft later used many of the arguments in this debate to create the Handbook of Christian Apologetics with then undergraduate student Ronald K. Tacelli, S.J..

Smile Empty Soul is an American post-grunge band from Santa Clarita, California.

Smile Empty Soul formed in 1998, while its original members were attending different high schools in the Santa Clarita area. The band, originally a three-piece group, consisted of vocalist and guitarist Sean Danielsen, bassist Ryan Martin and drummer Derek Gledhill.

After playing numerous hometown gigs, Smile Empty Soul ventured to the Castro District, and later passed a demo to John Parker of the West Hollywood indie label, ThroBack Records. That later led to a record deal with Jason Flom's Lava Records.

On May 27, 2003, the band released their self titled debut album Smile Empty Soul. The album was produced by John Lewis Parker, and three successful singles were released. In March 2005, the album was certified gold with sales in excess of 500,000+.

Sometime after the recording of their second album "Anxiety" was finished, drummer Derek Gledhill was replaced by Dominic Weir.

On September 22, 2005, during a concert at The Beaumont Club in Kansas City, Missouri, frontman Sean Danielsen stated that their new album Anxiety, would not be released due to issues with Lava Records. The band told fans that in order to receive the new album they could purchase one of a very limited number of burned copies or attempt to download the album online via BitTorrent.

Maximilian Karl Emil "Max" Weber (German pronunciation: [ˈmaks ˈveːbɐ]; 21 April 1864 – 14 June 1920) was a German sociologist, philosopher, and political economist who profoundly influenced social theory, social research, and the discipline of sociology itself.

Weber was a key proponent of methodological antipositivism, presenting sociology as a non-empiricist field which must study social action through interpretive means based upon understanding the meanings and purposes that individuals attach to their own actions. Weber is often cited, with Émile Durkheim and Karl Marx, as one of the three principal architects of modern social science.

Weber's main intellectual concern was understanding the processes of rationalisation, secularization, and "disenchantment" that he associated with the rise of capitalism and modernity. Weber argued that the most important difference among societies is not how people produce things but how people think about the world. In Weber’s view, modern society was the product of a new way of thinking. Weber is perhaps best known for his thesis combining economic sociology and the sociology of religion, elaborated in his book The Protestant Ethic and the Spirit of Capitalism. Weber proposed that ascetic Protestantism was one of the major "elective affinities" associated with the rise of capitalism, bureaucracy and the rational-legal nation-state in the Western world. Against Marx's "historical materialism," Weber emphasised the importance of cultural influences embedded in religion as a means for understanding the genesis of capitalism. The Protestant Ethic formed the earliest part in Weber's broader investigations into world religion: he would go on to examine the religions of China, the religions of India and ancient Judaism, with particular regard to the apparent non-development of capitalism in the corresponding societies, as well as to their differing forms of social stratification.