The difference between intellectual understanding and experiential realization is substantial. Experiential realization entails genuine attainment, enabling one to directly perceive the true suchness of their own mind in the present moment; what is observed is fact, a matter of direct perception. Intellectual understanding merely involves comprehending the principles, thinking that the Tathagatagarbha must be like that, without having personally realized it. Consequently, one cannot directly observe true suchness in the present moment. If one cannot engage in present-moment observation and practice in accordance with reality, it is impossible to genuinely align with and rely upon the true principle of suchness.
To better understand what the difference is, an analogy can be used. Intellectual understanding is like studying theoretical knowledge about apples—the theory can be mastered quite well and in considerable detail, covering aspects like the apple's origin, variety, transportation, storage, appearance, color, luster, and so on. Yet, since one has never actually tasted an apple, they remain unaware of its true flavor, how sweet and refreshing it is, and thus gain no real benefit for their body and mind. Experiential realization, on the other hand, is like having personally eaten an apple and truly knowing its sweet taste; the experience of the apple is real and undeniable, and both body and mind have already gained the benefit.
However, it is possible that the person who has eaten the apple cannot articulate its flavor very well and may know nothing about its origin or other details. Meanwhile, the person with intellectual understanding might know all the theoretical information about apples but has never tasted a single one. Thus, all their knowledge remains merely theoretical, yielding no actual benefit for themselves. It is like the dullest disciple of Shakyamuni Buddha who, after attaining the fourth stage of Arhatship, was unable to expound the Dharma principles of the path to liberation. Yet, he had already achieved genuine liberation, truly ended birth and death, transcended the cycle of rebirth, and would never experience even a trace of suffering in the future. In contrast, ordinary people today may possess very strong theoretical knowledge—not only are they eloquent and prolific in writings, expressing themselves like sages—yet within their hearts, there is not even a shadow of liberation. They may speak like sages, but in action, they are utterly ordinary beings. Their inner greed, hatred, and delusion remain completely unsubdued; their arrogance burns fiercely, and others dare not provoke them at all.
1
+1