Any experience is the coming together of three conditions: subject, object, and the interaction between the two. For example, I(subject) am talking (interaction) to you (object); or, you (subject) are listening (interaction) to me (object). Essentially, each of these three conditions is empty. Furthermore, if even one of the three conditions is perceived to be empty, then the other two are also automatically perceived as empty. You cannot attach to or contemplate one without the presence of the other two.
Contemplating and deeply penetrating this principle of causes and conditions leads to the experience of emptiness. A dry intellectual understanding of the interdependent nature of dharmas and the workings of conditionality, however, is vastly different from a direct experience. If they were the same, most of us would have already experienced prajna, and we would already be liberated.
Liberation Through the Gate of No-form