Light is measurable - darkness is an absence of light.
So - 'darkness visible' might indicate that a man who has achieved a degree or increase of light is now capable of being able to see his/her shortcomings and work on them. One could say that is how a good man can become better.
(Light can be depressing )
Our birth is but a sleep and a forgetting…trailing clouds of glory do we come from God, who is our home -Wordsworth
Masonic Work tunes sight to see both what is there and what is not there.
To "see" absence seems impossible but an acute observer "sees" things that are not there as well as what is there.
In the application of sight, seeing Darkness is not so much sensing the absense of Light, but viewing what is and determining the true nature of what is and isn't present.
Darkness is also a metephor for something that is ominous/threatening/undesired and hence seeing darkness is more of an indication of seeing something that is counter to what one would prefer rather than the absence of anything more prefered.
BTW - Depression is a stage one much go through to reach acceptance. Some do it faster than others. The degree one must experience is is directly proportional to the investment one has toward what one must let go of in relation to what one must eventually embrace.
Light is measurable - darkness is an absence of light.
Years ago I lived on a hill in Scotland and some people complained about being frightened on an unlit path that wandered through the center of the area. So I went out one night to investigate. It was a moonless night but there was some urban light reflected off the clouds.
At an intersection of the path I saw a dark cloud about 3 meters high moving around. I stepped into the cloud and immediately noticed that I could no longer see the dappled light on the path.
The dark cloud was thick.
I sucked out the darkness through my solar plexus passing the energy up through my crown until the cloud was gone.
After that there were no complaints about the path.
I noted that there had been a suicide close by about 60 years earlier.
I concluded from that experience that darkness is a presence and not an absence.
Many other observations of the presence of darkness followed
But that is unlikely to be the Masonic reference to "darkness visible". That is more likely to be a reference to how much more there is yet to be known, no matter what our stage of development.
Masonic Work tunes sight to see both what is there and what is not there.
To "see" absence seems impossible but an acute observer "sees" things that are not there as well as what is there.
.. to see (recognise) that something is missing? Like the capstone of the Great Pyramid, Black holes?
Even in the ordinary everyday experience, that would be a very valuable skill to have.
(I tried to point out recently that something is missing in mainstream Freemasonry, which creates a great gaping black hole in what Masons profess and what Masons practice - yep - recognition of Orders that admit women. Why can't we all meet on the Level? Needless to say it didn't go down too well with the men I was talking to :
A cute observer ;D
Our birth is but a sleep and a forgetting…trailing clouds of glory do we come from God, who is our home -Wordsworth