" That one body may act upon another at a distance, through a vacuum, without the mediation of anything else…is to me so great an absurdity that I believe no man who has…any competent faculty of thinking can ever fall into it. Gravity must be caused by an agent…but whether this agent be material or immaterial is a question I have left to…my readers. "

― Jeffrey M. Schwartz , The Mind and the Brain: Neuroplasticity and the Power of Mental Force