Keynes’s Philosophy of Mathematics Can’t Be Mastered by Reading the Notes of His Economics Lectures Made by His Students in the Years 1932–35

J M Keynes’s approach to the use of mathematics is based on his interactions with Bertrand Russell, Alfred North Whitehead, William Ernest Johnson, C. D. Broad, G. E. Moore, and Alfred Marshall. His views were carefully expressed in the A Treatise on Probability and General Theory. Keynes favored using systems of simultaneous equations both in the A Treatise on Probability and General Theory. A study of the student notes taken in the years from 1932 to 1935 alone will lead to the wrong answer regarding Keynes’s views on the role of mathematics and systems of equations in economics. Keynes’s philosophy can be expressed by the term Inexact Measurement or Approximation, which Keynes made the foundation for his inexact approach to measurement in probability, mathematics, and statistics.