When there is no answer book, the only way you can test something is by trial and error and a bit of luck. You need to do this to work out the extreme boundaries of what something is capable of. For example if you’ve designed a road car with a conventional piston engine and wanted to make it exceed a speed that has never being reached before, you are venturing into the unknown where it is up to you to find these boundaries. You can find this boundary out either by gradually increasing it in small steps until it fails, or going straight to the new extreme and hoping it works. Once the boundaries are discovered, in theory you should be safe if you stick within the boundary.
This technique works with many other things too. People creating new ideas such as a different style of music or art are also venturing into an unknown. When a musician writes a piece of music that is unique and revolutionary to the world (such as Berlioz's Symphony fantastic) , they too are venturing into the unknown. If popularity comes into it and it is a success, others will copy this style and know that they are safe as long as they stay within the limits. However people looking to explore further may push further through this boundary.
Overall we are not limited to these boundaries in life. They are just the limits of accomplishments that can always be pushed. New things are always being discovered and we are delving deeper and deeper into the unknown.