What is the sense and significance in general of life on the earth, and in particular of human life?
Interesting comments.
Something I'd like to point out about this question, is that although it does not deny the issue of personal, individual development, nonetheless the question is couched in wider social developmental framework.
Compare:
"Despite that in general life is there for any creature to use as they wish, what is the sense and significance of your personal life?"
"What is the purpose for humanity on this earth?"
Gurdjieff was very keen of individual 'salvation'. He was as obsessed with the possibility of an individual's survival after death, as he was with the whole question of the evolution, meaning and purpose of the human species. This is critical to him, as he was of a tradition which engaged in practical assistance for human evolution, as much as individual 'permanence'.
Traditions like Buddhism and Toltec are almost vehemently resistant to any consideration of wider social concerns - civilisations come and go, but the well remains the same. They are both in essence focused on personal realisation, and see the fate of the world as not just a distraction, but a temptation away from the primary, real purpose.
Gurdjieff's tradition, from the ancient Turkestan Sufies, and referenced constantly in his books, is very much engaged in the task of assisting humanity - it's ultimate purpose and goal as well as its current pragmatic problems.
The above quoted question echoes those considerations.
For myself, I maintain that the first question is, "Who am I?", in the fullest sense of that enquiry.
Then the question, "Why am I here?" which draws out the question of personal task and destiny.
Only then comes the question, "Why are we all here?" which is a natural evolution of the previous question.
My understanding of Gurdjieff, is that he would agree with that sequence, as it is the sequence of his own life's path. Just that I like to disentangle the threads, so that we don't begin at the wrong end - know thyself first, then serve.