In his Hypothesis of Light of 1675, Newton posited the existence of the ether to transmit forces between particles. The contact with the Cambridge Platonist philosopher Henry More revived his interest in alchemy.[91] He replaced the ether with occult forces based on Hermetic ideas of attraction and repulsion between particles. His contributions to #science cannot be isolated from his interest in #alchemy.[91] This was at a time when there was no clear distinction between alchemy and science.