It's not enough to say that at the heart of any depression are always ties: depression is the feeling of inability to break some bonds. But in fact, you can break any bonds if you start with the most pleasant and cherished.

We believe we begin to think when we start to reflect on an object or concept; but in fact, when we start to do this we just say to ourselves what we already know, or let's say potentially know, and this potential knowledge is a real mystery.
So in the end, being exhausted by thinking, we have to interrupt our thoughts and return to reality to re-charge the potential. The real mystery, therefore, occurs when we interrupt our thoughts (that's why the word 'intellectual' for me is rather dirty.)