Why Visualizing from Actual Visual Experience Is Easier Than Pure Imagination

What is seen firsthand includes the direct perception of the five sense consciousnesses and the concomitant mental consciousness, as well as the direct perception of the mental faculty. Because the mental consciousness has previously perceived it, this facilitates easier recollection by the mental consciousness. For what is not seen firsthand, neither the mental consciousness nor the mental faculty has experienced it; there is no direct perception, and it relies entirely on the non-valid inference of the mental consciousness. The mental faculty cannot exert its strength in such cases, making visualization more difficult. In the past, practitioners of skeleton contemplation had no physical skeleton to reference and relied entirely on meditative concentration for visualization. Nowadays, many skeleton models are available for direct observation as a reference. As long as one procures such a model and observes it daily, contemplating it day and night, the practice of skeleton contemplation becomes easier.