Humans think in two main ways: Ear (time, sequence, voice) and Eye (space, picture, layout). This short treatise gives a plain-English framework and a simple rule: state it in sequence; see it in space; keep them in round-trip agreement. It ties the Ear↔Eye split to development (hearing before birth, vision after), sketches a pendulum that has been Ear-heavy for centuries and is now swinging Eye-ward, and offers everyday checklists for writing, teaching, math (proof + “spine figure”), AI tests (text↔picture round-trip), and product design (dual views). Appendices include a Stages of Language sketch (spoken, meaning, writing, religion) and two simple figures for the pendulum.