There are many that argue that the universe is a chaotic chance generator, that the creation of life itself was simply an accident, and that accidents drive the sequence of events despite all the "best laid plans."
They may be confusing the element of surprise with accidents. Surprise can be part of the joy of living, when the unexpected erupts into the moment catching us unawares. The present may be the leading edge of existence, and yet, my sense of accidents is that they "happen" for a reason, and if that is true, they are not accidents at all.
People come into our lives seemingly by chance, simply sharing proximity, or mistaken identity, or colliding physically or mentally, and as time unfolds, we make meaning from such aleatoric encounters, often suddenly understanding that our lives have been immensely transformed in ways that are meaningful and decisive. Chance was the catalyst for change.
Was this predetermined? Pre-ordained? Events in motion, like filaments in an infinite tapestry shape the present in extraodinary ways. However, this is much different than cosmic events in which comets may collide with planets whether or not we are witness to the event. The difference of accidents within the domain of human experience is the conscious awareness of humanity experiencing and interpreting Time as emerging reality, a reality that is necessarily ambigious. The ambiguity provides a point of departure, so that our knowledge of the moment and truth is personal.
In one sense it is simultaneously "accident/no accident" and our experience and consciousness shapes this balanced yin and yang into some interpretation of the moment according to our predisposition. Since accident always includes its opposite, the debate of a universe governed by chance or structure is an inexhaustible discourse whose rhetoric may influence us in vacillating directions over time--never reaching a final resolution.