本稿の目的は,話し言葉による外化と数学学習における理解の関係を認識論的に考察し,ジグソー学習法に深い関わりを持つ数学教育における認識論を明らかにすることである。研究の方法は,認識論に関わる文献研究を行う。数学の認識論,数学教育における認識論のこれまでの議論を,話し言葉と数学学習における理解の関係の観点,Sfard,A.(1998)のメタファー論の観点から整理した。その整理の結果を基に,ジグソー学習法に深い関わりを持つ数学教育における認識論を明らかにした。数学の認識論は,大きく絶対主義と可謬主義に分けられる(Ernest,1991)。本稿で考察した9 種の数学の認識論のうち,話し言葉に関連する認識論として絶対主義の直観主義,可謬主義の規約主義,経験主義,準経験主義,社会的構成主義,文化人類学主義が挙げられた。話し言葉と数学学習における理解の関係について深く言及した認識論としては,社会的構成主義が挙げられた。数学教育における8 種の認識論のうち,話し言葉に関連する認識論として,社会文化主義,相互作用主義,社会的構成主義,文化人類学主義,多世界パラダイムが挙げられた。話し言葉と数学学習における理解の関係について深く言及した認識論としては,社会的構成主義が挙げられた。上記の認識論に関する考察を,メタファー論(Sfard,1998)の観点からも考察を行うと,数学の認識論は,絶対主義が獲得のメタファーに,可謬主義が参加のメタファーに対応した。数学教育における認識論では,行動主義,構造主義,急進的構成主義が獲得のメタファーに,社会文化主義,相互作用主義,文化人類学主義が参加のメタファーに,社会的構成主義が2 つのメタファーの接続に対応した。考察結果から,すべての子どもに対して意見の外化と議論を保障するジグソー学習法は,数学教育研究において社会的構成主義,社会文化主義,相互作用主義,文化人類学主義のいずれかを認識論的基盤とした学習方法論と成り得ることが示唆された。それらの中でも,数学の主観的知識から客観的知識が生成される過程を示す記述性,話し言葉を重視した数学学習のあるべき姿を示す規範性をもつ社会的構成主義は,現在のところジグソー学習法の認識論的基盤として有力な候補の1 つであると考えられた。, The purposes of this study are to investigate relation between externalization by oral language and understanding in mathematics education, and to clarify epistemology in mathematics education whichhas deep relation in a Jigsaw method. Method of this study is literature study on epistemology. Epistemology of mathematics and epistemology in mathematics education are analyzed from the standpoints of the relation between externalization by oral language and understanding in mathematics education, and from the standpoints of Sfard’s metaphors:acquisition metaphor and participation metaphor. Based on the analysis, it was clarified what kind of epistemology in mathematics education has deep relation in a Jigsaw method. Epistemology of mathematics is largely divided into absolutism and fallibilism by Ernest. Among nine types of epistemology of mathematics investigated in this paper, constructivism in absolutism, and conventionalism, empiricism, quasi-empiricism, social constructivism and anthropological approach in fallibilism are referred as epistemology relating oral language. And social constructivism is identified as an epistemology deeply referring to the relation between externalization by oral language and understanding in mathematics education. Furthermore, among eight types of epistemology in mathematics education investigated in this paper, socio-cultural approach, interactionist approach, social constructivism, anthropological approach and multi-world paradigm are referred as epistemology relating oral language. Again social constructivism is identified as an epistemology deeply referring to the relation between externalization by oral language and understanding in mathematics education. Investigating epistemology above mentioned from the standpoint of Sfard’s metaphors, absolutism is correspondence to the acquisition metaphor and fallibilism to the participation metaphor, in epistemology of mathematics. Regarding to epistemology in mathematics education, behaviorism, structuralism and radical constructivism belong to the acquisition metaphor and socio-cultural approach, interactionist approach, social constructivism and anthropological approach belong to the participation metaphor. And social constructivism is a connection of the two metaphors. In conclusion, it is suggested that the Jigsaw method which secures learner’s externalization of opinions and argumentation can be a learning methodology having epistemological basis of each of social constructivism, socio-cultural approach, interactionist approach or anthropological approach in research on mathematics education. Above all, social constructivism seems to become a strong candidate having epistemological basis for the Jigsaw method, because the social constructivism has not only a descriptiveness to account the process that mathematical subjective knowledge develops to objective knowledge, but also a normativeness to show true mathematical learning that emphasizes oral language.