This chapter explores the conjecture that tool use helped lay the foundations of key properties of modern minds: propositional meaning; wisdom and intuitions about meanings with their ineffable qualities and links to emotion; and our ability to walk, talk, and think about meanings at the same time. People need to react to similar things with similar thoughts and behaviors (generalization), while reacting to different things with different thoughts and behaviors. Differentiation within the behavioral systems of ancestral species must have advanced in tandem with differentiation of their mental and neural systems. Tool use clearly contributed to that differentiation. Such differentiation creates new challenges for grasping what mental states underpinning perception, the control of vocal and physical actions, and bodily reactions all have in common. The emergence of two meaning systems in a specific architectural arrangement is one plausible evolutionary response to those challenges.