Some things we can predict with great accuracy, simply because we can quantify almost all the variables that come into play. The path a bullet will follow when fired, how long it will take a brick to hit the ground when dropped, and how much fuel it will take to do 10 laps of Mount Panorama racetrack flat out.
It is when you start to introduce unquantified variables, as distinct from unquantifiable variables, that things get exciting. A strong gust of wind will change the trajectory of a bullet, and a prang on Skyline and subsequent braking and weaving will alter fuel consumption, but the impact of both can be reasonably accurately forecast if they are included in the variables considered.
It is the random events that really cause trouble, the kangaroo that jumps out half way down Conrod, the quick-handed apprentice that reacts to the brick heading for your toes and does a diving catch, these things cannot be reasonably forecast, are random events, but have a profound impact on the outcome.
The point of the story is to again confirm the old adage that strategy rarely survives the first contact with the enemy, so the more agile you can make your reaction to the unpredicted and just plain random, the more likely you are to come out on top.