This thesis elaborates different ways of looking at the relatively new field of economic theory, behavioral economics. Firstly, it was needed to represent the path of the new scientific discipline, from idea of bounded rationality to popular new paradigm of evolutionary psychology. To successfully introduce why on landacape of economic theory appears shift from orthodox view of rationality to irrational decision makers, better understending of cognitive arhitecture proposed by psychologists like Kahneman and Tversky is required. There are two systems, System 1 that is described as fast, automatic and intuitive, and System 2 that is decribed as slow, controlled and deliberate. Due to dissimilar modes of processing there is room for cognitive mistakes and systematic mistakes, biases. These systematic deviations conflicts with standard rationalistic view of economics. In this line, Kahneman and Tversky present their prospect theory. Prospect theory offers some new parameters like loss aversion and reference point. But how much is changed by new prospect theory? By some critics, not very much. New behavioral program still holds its grounds on conventional wisdom. Except for few new variables in utility function nothing else is changed. Also, researches are often gulity of bias bias. Meaning, they are finding biases where there is none and where human intuition is right. In that manner, a new paradigm in behavioral economics arises, influenced by findings in evolutionary psychology. From evolutionary past we devoloped „adaptive toolbox“, set of heuristics, cognitive mechanisms that helps us dealing with specific taks in our enviroment. This fast and simple heuristics are often more sufficient than far more complex models and strategies. Where is a place for philosophy in all of this? Surely, in new terms of nudges and libertarian paternalism created by Thaler and Sunstein. Are nudges ethically legitimate and should we neglect our autonomy for more rational choices in eyes of choice architect? These are just some of the questions to mention a few. Several subdisciplines of behavioral economics are also discussed. For one, there are behavioral finances. Efficient market hypothesis can be attacked from many angles and critic can be traced far back to Keynes and his groundbreaking work General theory. At the end, there is neuroeconomics, subdiscipline that can inform economics with valuable neuroscientific data.