Analytic epistemology has long focused on the sufficient conditions of knowledge, yet systematically neglected the dynamic problem of how knowledge is transformed into action. Virtue epistemology addresses the cognitive agent's competence, and the philosophy of action distinguishes knowing-that from knowing-how, but a unified framework concerning the transformation mechanism between them remains absent. This paper proposes a Five-Dimensional Approximation Model: for any target task, an agent holds an analyzable five-dimensional operative configuration 〈B, S, R, D, I〉 (Boundary, Structure, Reserve, Direction, Intensity). Knowing is not a mirror reflection of the subject upon the object, but a grinding process in which the agent's imagined five-dimensional configuration approximates the task's real five-dimensional configuration; the global mismatch degree δ between configurations determines the accumulation of observability. The paper distinguishes two modes of conscious processing: Heavy Consciousness (convergent, logical, serial) and Light Consciousness (divergent, intuitive, parallel), reconstructing dual-system theory as two granularities in the approximation process. The obstacle to the knowledge-action transformation is remodeled as an epistemic condition problem: action is authorized to initiate if and only if δ falls below an action threshold θ_act. The paper argues that this model is compatible with the active inference framework in predictive processing theory, yet provides the multi-dimensional diagnostic tools that the latter lacks.