 The introduction of Newtonian natural philosophy into this discussion had ambiguous consequences depending on the interpretations given to Newton’s natural philosophy. Newton’s Philosophiæ Naturalis Principia Mathematica (Mathematical Principles of Natural Philosophy) of 1687, with subsequent revised editions in 1713 and 1726, developed a fundamental critique of Cartesianism, and also introduced the concept of “attraction at a distance” into physical explanations. Extending the concept of “active powers” to the micro-level in the Opticks of 1704 (English), with important revisions in editions of 1706 (Latin), 1717, 1721, and 1730, Newton introduced into biological discussions new issues that played out in complex ways in the subsequent decades.