Literally: submerge – exist – mind – know
Alternately: Subconscious. This modern compound comprises 潜在, “dormancy,” and 意識, “awareness,” and stands in contrast to terms such as 前意識 (zenishiki, “preconscious”) or 無意識 (muishiki, “unconscious”).
Notes: I have nothing more to add about the phrase itself, but I did want to comment on the so-called “collective unconscious” (集合無意識, shuugou muishiki). While mystical misreadings of the term hold this up as some sort of unbodied supernatural repository of eternal Platonic truths, all it really refers to is… tropes. If an idea is used multiple times in a given culture, it enters the consciousness of many people (i.e. it becomes “collective”) but most people aren’t consciously thinking about it (i.e. it’s “unconscious”).