As a first step in remedying this disparity between tradition and positive psychology, Peterson and Seligman set out to identify, organize and measure character. Peterson & Seligman began by defining the notion of character as traits that are possessed by an individual and are stable over time, but can still be impacted by setting and thus are subject to change. The researchers then started the process of identifying character strengths and virtues by brainstorming with a group of noted positive psychology scholars. Then, Peterson & Seligman examined ancient cultures (including their religions, politics, education and philosophies) for information about how people in the past construed human virtue. The researchers looked for virtues that were present across cultures and time. Six core virtues emerged from their analysis: courage, justice, humanity, temperance, transcendence and wisdom. Next, Peterson and Seligman proposed a model of classification which includes horizontal and vertical components. The hierarchical system is modeled after the Linnaean classification of species, which ranges from a specific species to more general and broad categories. The scientists stated the six core values are the broadest category and are, “core characteristics valued by moral philosophers and religious thinkers” (p. 13). Peterson and Seligman then moved down the hierarchy to identifying character strengths, which are, “the psychological processes or mechanisms that define the virtues” (p. 13). The researchers began the process of identifying individual character strengths by brainstorming with a group of noted positive psychology scholars. This exercise generated a list of human strengths, which were helpful when consulting with Gallup Organization. Peterson and Seligman then performed an exhaustive literature search for work that directly addresses good character in the domains of, “psychiatry, youth development, philosophy and psychology” (p. 15). Some individuals who influenced Peterson and Seligman's choice of strengths include: Abraham Maslow, Erik Erikson, Ellen Greenberger, Marie Jahoda, Carol Ryff, Michael Cawley, Howard Gardner, Shalom Schwartz. In an effort to leave no stone unturned, the researchers also looked for virtue-laden messages in popular culture. For example, the researchers examined Hallmark greeting cards, personal ads, graffiti, bumper stickers and profiles of Pokémon characters. After identifying dozens of ‘candidate strengths’, the researchers needed to find a way to further refine their list. Therefore, Peterson & Seligman developed a list of 10 criteria (e.g., strengths must contribute to a sense of a fulfilling life, must be intrinsically valuable) to help them select the final 24 strengths for the CSV (see CSV for complete list of criteria).