What is and is not possible? That question has, possibly, had more written about it than any other. Is possible that which can be expected to happen? But far too much has happened that was once believed impossible for that to be a good answer. Perhaps it would be easier to work from the other side, how do we hedge in the impossible? Theoretical occurrences that violate the laws of our everyday existence are termed magic or supernatural. But, of course, many would argue that these things can and do happen. Almost every religion has part of it's founding dogma that the supernatural has happened at least a handful of times. And if any of these mutually contradictory claims are in fact correct it would in turn make the label of supernatural worthless as anything that happens in nature is by definition a part of it. If the supernatural refers to God interfering with the normally operating laws of the universe then that means he had to have built into those laws the possibility of his own future meddling, making them also part of the laws of the universe. Divine intervention would be a feature and not a bug. If the supernatural real then it isn't, so by definition the supernatural only refers to what cannot happen. So we limit ourselves only to that which lies within the circle drawn by the laws of physics. But can we be sure of those? Some physicists worry that the laws of physics may differ across vast regions of space. It is possible that physical constants are not constants at all but variables whose shift can only be detected on the inter-galactic scale. After all, how would we know? We can only perform real tests in our own little system. We look to the stars and see that everything seems to follow the same rules we observe on Earth, with a few yet to be understood wrinkles, but what about all we cannot see? Those wrinkles may in fact reveal holes in our understanding of nature and of what is in fact possible.
So perhaps to arrive at what is possible we should start at the beginning with what know to be true and certain and universal. And what, ultimately, do we know for certain? Descartes gave us the axiom that all we truly know is real is ourselves. The famous Cogito ergo sum. It's a better place to start than most but like all axioms it must hang alone unproved. Can we really prove to ourselves that we think and therefore are? Is it not possible that our perceived thoughts are little more than memories, a story constructed by our brains to make sense of the actions we took and therefore improve our future predictive ability even though those actions were in fact done without thinking? It's possible that we are in every moment unconscious automatons and consciousness only exists in retrospect. But, of course, if we pursue that thinking we are forced to ask, if this isn't consciousness then what is? We have nothing to compare it to and so consciousness either refers to this or it refers to nothing and so now we see the pull of Descartes' axiom. After all we must start somewhere. But there is value to be gained in this exercise in that it brings us to ask if there are other places to start. Other axioms. I can think of one. Possibly older than Descartes' if it was, in fact, invented by Hassan-i Sabbat, founder of the Assassins. More likely it was invented later, perhaps by Neitzsche who certainly popularized it and may have only attributed it to the Order of Assassins for the air of age and mystery the association created. The axiom is this: Nothing is true, everything is permitted. Regardless of its origins it is hard not to agree with Neitzsche that herein lies a path to true freedom. To take as your axiom that there is no truth that can be given to you and that there is nothing other than yourself that can determine what you can and can not do. That it is up to each one of us to determine for ourselves what is true, and what is possible.