No one can stop a child from playing by leaving him inactive; rather, the child can be stopped from engaging in nonsense by being engaged in superior activities. Similarly, the forceful restraint of sense activities by the eight principles of yoga is recommended for inferior men; superior men, being engaged in the superior activities of Kṛṣṇa consciousness, naturally retire from the inferior activities of material existence.
In this way Lord Caitanya teaches the science of Kṛṣṇa consciousness. That science is absolute. Dry mental speculators try to restrain themselves from material attachment, but it is generally found that the mind is too strong to be controlled and that it drags them down to sensual activities. A person in Kṛṣṇa consciousness does not run this risk. One therefore has to engage one's mind and senses in Kṛṣṇa conscious activities, and Lord Caitanya teaches one how to do this in practice.