Our materialistic way of life is described as gṛha andha-kūpam (SB 7.5.5). This family life is just like dark well. We are already in the darkness, and another darkness is to fall in the dark well. If one falls down in the dark well, it is very difficult to get out, because he may cry very loudly and people may not hear. These dark well are sometimes there in the paddy field.
I have seen one dark well. In your country, when I was guest in John Lennon's house in 1969, we saw in the garden there was a dark well. Dark well means a very deep ditch, well, but it is covered with grass. You cannot know that there is a deep well, but while walking, you may fall down within it. And it is already covered with grass, and it is very deep. If you fall down and you try to get out of it, because it is lonely place, nobody is there, nobody may hear you, and you may simply die without any help.
So this materialistic way of life, without any knowledge of the outside world or without any knowledge . . . outside world means just like we are within this universe. It is covered. The round thing which we see in the sky, that is the covering. Just like a coconut shell: a coconut shell, within and without. Within the coconut shell it is darkness, and without it is light. Similarly, this universe is just like the coconut. We are within.