著者：細谷 忠嗣1,2（firstname.lastname@example.org）・伴 和幸2,3,4・大渕 希郷2・西村 直人2,5・田川 哲2,6・御田 成顕1・太田 徹志1・楠戸 建7・雷 陽7・三木 望7・穆 云妹7・白新田 佳代子7・宋 閻徳嘉7・齊藤 礼3・椎原 春一3
所属：1 九州大学持続可能な社会のための決断科学センター；2 Wild meǽt Zoo；3 大牟田市動物園；4 星槎大学大学院教育学研究科；5 糸島ジビエ研究所；6 島根県東部農林振興センター；7 九州大学持続可能な社会を拓く決断科学プログラム
Abstract: Institute of Decision Science for a Sustainable Society (IDS3) researches the methodology of decision making in uncertain situation. IDS3 offers various practices and experiences of problem solving. Particular instances of decisions are accumulated. However, the concept of decision that Decision Science focuses on is still undefined. Here I show that conditions of decision are (1) that it is made in uncertain situation, (2) that the agent exist, and (3) that it is socially justifiable. IDS3 has two models of the process of decision making, Y-model and G-model. Y-model claims (Y1) that decision that Decision Science focuses on is decision-making for big social issues and (Y2) that it cannot be selected by preferences. G-model claims (G1) that decision is subclass of determination and (G2) that we have autonomy and responsibility for what we decide. In this paper, I analyze the concept of “decision” in order to find the logical properties of decision. I concluded that combined model is valid framework of decisions and we can categorize four kinds of decisions according to the kinds of uncertainty of situations. My conclusion demonstrates that as well as how we categorize various kinds of decisions, the social justifications of particular decisions are dynamics for a course of problem solving.