Which Consciousness Performs the Function of Thinking?

Thinking is divided into shallow-level thinking and deep-level thinking. Shallow-level thinking is the mind consciousness thinking alone, somewhat like a cursory glance at flowers from horseback; deep-level thinking is thinking carried out jointly by the mind consciousness and the manas, which requires meditative concentration. When meditative concentration is insufficient, thinking remains only on the surface of the mind consciousness and cannot penetrate to the manas; consequently, one cannot truly think things through and understand, cannot truly solve problems, and the doubts in one's mind still cannot be resolved.