Contemporary debates over plant cognition, slime mold learning, and bacterial behavior share a common dysfunction: biological observations are held hostage to terminological verdict. Before a phenomenon can be understood, it must first be judged — does it qualify as cognition? Does it rise to the threshold of consciousness? This paper argues that the dysfunction is not empirical but conceptual, and that its roots lie in a three-century philosophical inheritance that severed sensation from knowing. Tracing the genealogy of both cognition and consciousness from their sensory origins through Cartesian bifurcation to the computational turn, the paper shows that both concepts have been progressively abstracted until the living organism that originally grounded them became invisible. What replaced it — first the rational soul, then the information-processing machine — shares a single structural feature: the elimination of sensation as constitutive of understanding. Against this inheritance, the paper recovers a principle articulated by the Scottish physician Robert Whytt in 1751: that the original constitution of living frames is to sense disturbing conditions and be driven toward their resolution. This functional description — here termed the Sentient Principle — holds at every scale of living organization, from bacterial chemotaxis through slime mold habituation and plant systemic signaling to the reflexive self-awareness of vertebrate consciousness. It does not require terminological authorization at any level. It requires only careful functional observation of what living systems actually do. The paper proposes a methodological inversion: rather than defining concepts and judging whether phenomena qualify, begin with the phenomenon, characterize its functional structure, and locate it within the continuum of sentient organization. This inversion dissolves the standard debates without dismissing the observations that generated them — and opens a path toward comparative biology that is genuinely descriptive rather than terminologically gatekeeping.