I had the good fortune of meeting Father Javier through a Jesuit network to which we both belonged. When we first met, he was its coordinator. A few years later I succeeded him in that job. He was very nice and kind, generous and gracious. He was very passionate about our apostolate of Jesuits in Science. The word "apostolate" does not mean that a Jesuit scientist goes to his laboratory to preach to his co-workers. Our apostolate is about being with other people, reflecting in the light of faith on our shared experience, and being there for others when they need us. It is a very low-key presence. Javier was one of the great masters of the unpretentious and unassuming. He was fully devoted to his mission, convinced and convincing others that God can be found in all things, and particularly in his beloved mathematics.
Born in Valencia, Spain on Jan 7, 1942, he joined the Society of Jesus on Aug 14, 1959. He studied in Barcelona, Zaragoza, Frankfurt am Main, Madrid, was ordained to the priesthood on July 14, 1973 in Valencia, and obtained his doctorate in mathematical logic in Freiburg im Breisgau in 1977. He taught at the Complutense University in Madrid in 1977-2012 (public research university; full professor at the School of Information Science). He was very active with the Christian Life Communities (national director 1984-86). He was the European coordinator of the Jesuits in Science (2001-2006), and coordinator of the Spanish group of reflection on the Jesuits in Science (2014-2016). He was the founding head of the Chair of Science, Technology and Religion at the Pontifical University Comillas in Madrid (2003-2012). He died in the early morning of Aug 3 in Madrid.
Here are two videos. The first presents his book on mathematics and religion. Here is the transcript:
In my book I distinguish between the language of sign and the language of symbol. The language of sign is the language proper to mathematics. It's a language that has formal models. It's objective. In Spain, in America, in China, in every culture, in every human situation this language has always the same meaning. The language of symbol expresses personal, metaphysical ideas about the last meaning of reality. My idea is that we cannot separate the language of signs from the language of symbols. Because among them there is a relationship of complementarity. But this complementarity is not symmetrical. Because both languages refer to different aspects of the same reality. The language of sign refers to the more objective, manipulable aspect of reality. The language of symbol corresponds to the more metaphysical and religious aspect of reality. The ethical question is very important. We need science to transform the world. We need science to have a better world. But there is the question of being good. And I'd say that usually it's more important to be good than to be a good scientist. The interaction between science and religion has not been always the same. In the future, the language of sign, that is the language of mathematics, would be more and more important. But we know the limitations. We need the language of symbols to express the deep dimensions of humankind, the religious dimensions of humankind, that shoud be taken into account for our decisions.
The second a beautiful obituary published on facebook (you will probably need a facebook account in order to view it). Here is the English translation:
Javier Leach was one of the many men and women who have encountered in science footprints of a marvelous work of God. A man who followed the star of a great Jesuit tradition desirous of discovering in the world new paths to dialogue between science and religion. We owe to Leach the formulation of the NOSYMA model (not symmetrical magisteria) to explain the relationship between science and religion. Two insepaarble and complementary but not symmetrical areas of knowlege. Science works in an autonomous form while religion only needs the scienific language to maintain a better dialogue with contemporary society. Leach was a great exporer of God in all things and encountered Him more particularly in the most elementary, eternal and beautiful of His creation - in mathematics.