"What is truth? by W. D. Wattles" is a metaphysical-philosophical treatise written in the early 20th century. It explores the nature of reality—time, space, substance, consciousness, motion—and argues that a single conscious, divine substance underlies all things, shaping the world through will; its central topic is how aligning with this reality leads to human health and abundance. The book proceeds step by step: time and space are real, boundless frameworks; the many “materials” are forms of one fluid substance that can become solid or ethereal by pressure and motion. Consciousness belongs to substance itself, not to empty space or mere brain activity; in humans it can expand toward completeness. Motion is substance shifting in space and time, and every “force” reduces to pressure of substance—there is no attraction across a vacuum. The origin of motion is the will of Original Conscious Substance (God), whose will-pressure produces light, heat, gravity, and chemical affinity, and whose motive is the happiness of all. Man, as conscious substance in a human form, can cooperate with this will; by persistently recognizing divine life and abundance—through affirmation, prayer, and alignment—he becomes whole in health and supplied in all needs, while the habitual recognition of disease or lack perpetuates them. (This is an automatically generated summary.)