It seems a pretty general claim of many religions, and is confirmed by the intuition of many individuals; that this is in some sense a 'fallen world'.
By which I mean that there is a conviction that - compared with conditions in mortal life on earth - in some way there was a past era of innocent, blissful happiness. Some 'Garden of Eden' for instance.
I agree that this is broadly the case, but my understanding of how and why this world is 'fallen' is probably unique.
I thought it would be an interesting exercise to try and set-out clearly and concisely how I understand this business.
I regard life much as do Mormons; divided into
1. Pre-mortal spirit life - when we were innocent and childlike spirits, living under the direct influence of God.
To become mortal Men is to opt-out of pre-mortal spirit life.
2. The first great transformation is birth into mortal incarnate life (a world of 'entropy' - of change, degeneration and death) - which we chose to experience, as the necessary pathway to fuller divinity.
3. The second great transformation - for those who choose to follow Jesus Christ - is death and resurrection to immortal and incarnate life; to dwell in a Heaven peopled by God, Jesus Christ, Lazarus (the first resurrected Man) and all the people who have gone before us.
To become a resurrected Man is to opt-in to Heaven.
The 'move from pre-mortal spirit life into this earthly word was either involuntary or voluntary.
Satan and the demons were spirits who were involuntarily expelled from pre-mortal bliss (because of their prideful, resentful, opposition to that state); and who are now bound to the fate of this world (unless they instead choose utter isolation): the demonic spirits cannot move on to Heaven, cannot be resurrected.
In addition this earthly world is peopled by mortal incarnates such as you and me; who chose to get temporary bodies with the possibility of gaining an eternal body; and who experience situations of this earth with the possibility of learning and developing from them. We can die, leave the world, and move-on to Heaven.
So this earthly world we inhabit is a mixed world; inhabited by both mortal incarnates and demonic spirits. Our dwelling here is indeed a fall for incarnate Men, in the sense that we are no longer innocent, and are beset by evil.
Whereas our pre-mortal life was blissful in the same kind of way that we can imagine the happiest possible young childhood in the best possible family - but our current life is not.
We have gone from a life in which simply to be alive was a joy, but where we were unfree and going nowhere; to a life where we may be agents free to choose or reject Heaven; and whose primary purpose in living is to learn from our experiences (which may be various mixtures of happy and miserable, according to need).
This mixed mortal life is indeed well-designed for its core purpose of providing learning-experiences for Men - especially because God tailors each individual's lived experiences to that individual's greatest needs.
Therefore, 'fall' does not wholly capture the transition into this world - because this world is the best place for doing that which this world is set-up to do.
So there has indeed been a fall, in terms both of lesser happiness, and also the pervasive and unavoidable presence of sin (which includes all forms of entropic change).
But at the same time incarnation brings potentially (if we so choose) an increase in freedom. As we become bounded by bodies so we are less influenced by the divine and reach a point when our affiliation (with, or against, God) must be chosen - much as an adolescent faces the choice whether to re-affiliate-with - or reject - family.
Yet, on the other hand, this mortal life is a necessary 'upward' step if we wish to become more fully divine; with divinity being defined in terms of becoming able - consciously and by choice - to participate in God's ongoing creation.
So yes, this is a fallen world - less happy than pre-mortality, and permeated by evil in ourselves and others. This is a life of inevitable entropic change - hence 'pain' is inevitable. And we can be finally rescued from evil and pain only by death and resurrection.
But this life is not necessarily miserable and evil all of the time (this would be extremely rare); rather, this mortal life is not about every-body being-continuously-happy and sinless.
Instead this life is in essence a time of transition, learning and choices: that is what this life is for.
And, the exact purpose of this mortal life also differs for each individual Man - since all Men differ innately.
This mixed mortal life is for the Heavenly life to come... Which doesn't at-all mean this life is un-important in its own right. On the contrary this mortal life is vital. But the importance of mortal life derives from its being underpinned by the possibility of eternity.