OK, change that to ALMOST always. If, as you claim, I don't know what I'm talking about, then the counter-claim is that the sun is NEVER visible during full overcast.
I will not debate this with you. Too many years sailing out of Boston Harbor, in weather fair and foul, have taught me otherwise.
Okay, since my primary objection was to the use of "always", I'm satisfied. Although my experience has been more along the line the sun is sometimes visible through a full overcast.
To let you know where I'm coming from, the majority of my sea time was the W Pacific, but I've been in every major basin except the Arctic and the S Atlantic.
Also, in the Navy on ships without aerographers, which was every ship I was on, navigation was responsible for the hourly weather observations. So between celestial and weather obs, I've spent a lot of time looking at the sky at sea.