While the study of Newton's religious views has been continuously expanding, it has not been brought to bear directly on Newton's career as an ‘experimental philosopher’. Historical perspectives on his optical experiments in particular affirm the historiographic separation between the religious and scientific aspects of his work. In this paper I examine the practical implication of Newton's theology of dominion on his early experiments on light and colours. While his predecessors had made experiments to collect evidence, I show that Newton conceived experimental research as a discipline of the practical understanding of the structure of light and the origins of colours. His conception of experimental reasoning followed his practical reflections on human beings as agents who belonged to God's dominion and who were created to serve its divine ends. These reflections suggested, more specifically, that the aim of natural philosophy was the discovery of divine rules that instrumentally constrained and facilitated human conduct in general, and perceptual judgement in particular. I show, moreover, that Newton's endeavour to subordinate experiment to divine worship had been foreshadowed by Boyle's writing on the theory and practice of the experimental philosophy.