We live in an age of science. This research proposal entitled ‘Changing Tools: An In-Depth Study of the Development of Isaac Newton’s Scientific Methodology, and its Impact and Significance’ seeks to contribute to a better understanding of (the development) of Western science which is of vital importance to address the contemporary issues that we are faced with (e.g. climate change). We do so by focussing on the mathematical physics and scientific methodology of one of the greatest scientific minds our culture has produced: Isaac Newton. This research proposal seeks to contribute to the history of scientific methodology, and hence to a better historical understanding of the development of our scientific methods which are major accomplishments of our scientific culture, and to a better understanding of how mathematics establishes and secures knowledge claims in physics. This proposal has three important goals: 1. to trace the development of Newton’s scientific methodology from his early optical work in the 1670s to the publication of the third edition of the Principia in 1726; 2. to explore the impact of Newton’s scientific methodology on eighteenth-century physics; and 3. to explicate what we can learn from Newton’s work about the ability of mathematics to establish and secure knowledge claims in physics.