“Are not gross Bodies and Light convertible into one another, and may not Bodies receive much of their Activity from the Particles of Light which enter their Composition?”
Newton poses a speculative question about relationships between matter and light, illustrating how the later Queries of Opticks use open questions to push beyond the book’s demonstrated optical results.
Source details
Opticks, Query 30, represented from the fourth corrected edition text (1730) by Inters.org. Newton states this as a question within his historical natural-philosophy speculation; it is not presented as a modern account of particle physics or matter–energy conversion.