" The critical philosophy of science became as it were negatively metaphysical--in other words, materialistic--on the basis of an error of judgement; matter was assumed to be a tangible and recognizable reality. Yet this is a thoroughly metaphysical concept hypostatized by uncritical minds. Matter is an hypothesis. When you say "matter," you are really creating a symbol for something unknown, which may just as well be "spirit" or anything else; it may even be God. "

― C.G. Jung , The Portable Jung