Born at Keta, Ghana, Baëta studied at the Scottish Mission Teacher Training College, Akropong, Ghana, Evangelisches Missionseminar, Basel, Switzerland, and King’s college, London, where he wrote a doctoral dissertation entitled “Prophetism in Ghana.” He was ordained in 1936. In 1938 he participated in the meeting of the International Missionary Council (IMC) at Tambaram, India.
He was Synod Clerk (chief executive) of the Evangelical Presbyterian Church (1945 – 1949) and chair of both the Ghana Christian Council and the Ghana church union negotiations committee. In 1958 he became the vice-chair of the IMC and superintended the merger of the IMC with the World Council of Churches (WCC).
He was the Henry W. Luce Visiting Professor at Union Theological Seminary, New York (1958 – 1959), and the Edward Cadbury Visiting Professor at Selly Oak Colleges, Birmingham, England (1965 – 1970). He also served on the Commission of the Churches on International Affairs, the Central and the Executive Committees of the WCC, and the Anglican-Reformed Commission on Church Unity. He was involved in Bible translation, particularly into Ewe.
Between 1949 and 1971 Baëta served on the staff of the divinity department in the University of Ghana. He helped shift this department from emphasizing Christian theology to emphasizing religions and theology in a pluralistic world. Baëta voiced the concerns of younger churches engaged in mission, and pioneered on the African continent in shifting from mission understood as an expression of worldwide Christendom to mission viewed as encounter and peaceful coexistence of persons of different faiths.
In his thinking, ecumenism and mission were inextricable. His conviction that God was sovereign over all of life led him to accept political responsibility: as a member of the Legislative Council of the Gold Coast (1946 – 1950); member of the Coussey Committee on Constitutional Reform for the Gold Coast; and member of the Constitutional Assembly, which, after the overthrow of Kwame Nkruma, prepared the way for return to civilian rule. Thus, for Baëta evangelism and engagement with issues of peace and justice were already in the 1940s and 1950s inextricably linked.
John S. Pobee