In an unthinkable case you have never had a master, if you do still strive to follow the path of the samurai you may find yourself a little bit confused. You’ve developed your fighting skills to perfection, become an ardent master of the quill as well as of the sword, and even followed the four vows… well, only three of them—the second one assumes you do, in fact, have a master.
You might call yourself a ronin, but that would be larping without substance. After all, all ronin used to have masters, and it would be an utter disgrace to let yours die and then go on living your life after the fact.
One option remains. Could a samurai serve an ideal, or a grandiose project? It turns out there were historical precedents. Some had even abandoned their clans and were officially condemned and hunted. Most likely, they didn’t pledge fealty to an ideal in any formal way—though we may never know of the private rites that took place—yet they served dutifully the grand vision of national transformation, or scholarly achievement, or religious endeavor.
So if you seek to reconcile your samurai longing with the real-world circumstances, choose this. Define the most important enterprise and devote yourself to it.
As I understand it free will is a manmade construct as is god. we think we know the thoughts and intentions of god because we made all that shit up anyway. Otherwise, it would be impossible to know the thoughts and intentions of an omniscient entity.