Jens Erik Fenstad is a Professor Emeritus of Mathematics and former Pro-Rector of the University of Oslo, Norway. He was the Chairman of the Standing Committee for the Physical and Engineering Sciences of the European Science Foundation, a former President of the International Union of History and Philosophy of Science, and past Chair of the UNESCO World Commission on the Ethics of Scientific Knowledge and Technology. He is the author of several books including “General Recursion Theory”, “Nonstandard Methods in Stochastic Analysis and Mathematical Physics”, and “Grammar, Geometry and Brain”.

• 1.Preface.- 2.Introduction.- 3.Mathematics and the nature of knowledge – an introductory essay.- 4.The miraculous left hand – Leonardo and the nature of knowledge.- 5.Relationships between the social and natural sciences.- 6.Changes in the knowledge system and their implications for the formative stage of scholars.- 7.Remarks on the science and technology of language.- 8.How mathematics is rooted in life.- 9.Tarski, truth and natural languages.- 10.Formal semantics, geometry and mind.- 11.Discours, Interaction and Communication.- 12.On what there is – infinitesimals and the nature of numbers.

“This book collects eight essays … . there is much to be learnt from this collection for the reader who is prepared to make the effort to interrogate Fenstad’s thoughts … provided him with a deep appreciation of the role of mathematical modeling in the development of scientific knowledge. … As for who the interested reader might be, I see four potential candidates: well-educated lay people … philosophers of mathematics and philosophers of science … .” (Julian C. Cole, Philosophia Mathematica, July 9, 2022)