One Dark Night

John of the Cross utilizes the first few stanzas of his poem, The Dark Night of the Soul, as a medium in which to better understand The Ascent. Darkness is a metaphor for the complete mortification of the senses. To deprive oneself of the gratification of the appetite for all sensate phenomena, the disease of desire is cessated. In Buddhism this has to do with Āyatana, or everything under the sphere of the senses:

*eye and visible objects
*ear and sound
*nose and odor
*tongue and taste
*body and touch
*mind and mental objects

In post-canonical formulations the following chart breaks this down even further:

In line with Dependent Origination and the Aggregates the following is in order:

(Wiki)

We can see therefore that “the senses” incorporates all of the above; indeed, they are also directly responsible for all subsequent karmic actions, keeping one on the perpetual wheel of dukkha and rebirth. So it’s essential that they all be mortified in order to transcend Mara’s Samsaric-Curse and be re-united with the Essential Self in the Unborn Mind. Thus by depriving oneself the sensate gratification of all the above the adept now lives in darkness and in a dark-void with respect to them all. Hence, all the apparent sovereignty of the Lord of the Senses is utter slavery as compared to the Lord of the Imageless Unborn Spirit.

The path and ascent to the Unborn, then, requires that one habitually renounce and mortify all of the sensate appetites. The sooner this is initiated the better the opportunity for Divine Union. But until these mortifications are practiced one will not achieve union no matter how great one’s virtue is; yea, Perfect Virtue consists in keeping the Mind empty, void, and thus purified from the realm of sensate attachments.