"May the Force be with you", one of the most remembered phrases of Star Wars, emphasises the predominant role that 'the Force' plays in the Star Wars universe. In the stories of episodes IV to VII, normal people don't believe in the Force in spite of it being ubiquitous according to the Jedi. In sum, they are oblivious to the obvious. Quoting Obi-Wan Kenobi for example "It's an energy field created by all living things. It surrounds us and penetrates us; it binds the galaxy together".
It is not crystal clear what is fully implied by this description but, to the Jedi, the Force contributes to every unfolding event, from the life and death of living species to the structure of the galaxies.
To the spectator, the Force of Star Wars is very mysterious and appears to be unfathomable. After all, in the real world we know what a force is...or do we?
Of course, the concept of force is colloquially used to mean "pushing" or "pulling" something, such as with our hands or with the help of machines. But how do we talk about all the other phenomena which occur without us actually doing anything?
This questioning was predominant in ancient Greek philosophy where a distinction would be made between "natural" forces governing the behaviour of Heavenly and Earthly phenomena -- often drawing from Aristotle's theory of the five elements -- and "un-natural" forces which would oppose these natural forces; like when one tries to lift a rock for example.
The narrative changed in the 17th century when Isaac Newton proposed a unified approach of forces and of both Earthly and Heavenly phenomena. The biggest leap was made by stating that there exists a universal gravitational attractive force between any two objects in the universe no matter how far they might be from one another. This same force would be responsible for things as seemingly different as the orbit of planets and the fall of an apple on Earth.
From Newton's ideas emerged novel proposals like that of Roger Boscovich who suggested in the 18th century that maybe all matter is made of a force acting between point centres, nothing more. This is not without similarity with the outreaching explanatory power of the Force in Star Wars.
Going back to Star Wars, the knowledge of the Force is not fixed in time. Due to their specific affinities with the Force, the Jedi and the Sith improve their understanding and mastery of it through experimentation. Hence, at the pinnacle of the Jedi era in Star Wars Episode I, we learn that there exist two types of Forces: the Living Force and the Cosmic Force, the second being fed by the first. In episode III, we learn that Darth Plagueis -- Palpatine's master -- had achieved control over life itself via his own relentless research on the Force. Incidentally, at the very end of the same episode we also learn that the Jedi master Qi Gon Jin's research on the Force lead him to discover a way to communicate with other Jedi after his own death. Some technologies, like the iconic light sabres, rely heavily on the Force and in particular on so-called Kyber crystals - natural crystals which are in tune with the force.
Interestingly, the same applies to our own understanding of forces in the real world: it is changing with time. To some contemporaries of Newton and later commentators, the universal force of gravity he had introduced that could act at any distance was so mysterious that it was argued he was going back to using "occult ideas".
Another similar force called the electromagnetic force was soon discovered and it was shown to be related to the deformation of an invisible field filling space in its entirety; the electromagnetic field.
Other fields were later discovered and, in the most current picture we have of the world, we are all made of matter fields coupled to one-another via three fundamental force fields (weak, strong and electromagnetic). If it were not bizarre enough it turns out that Newton's gravity still resists being fitted in this model of "field theory" and is currently understood as being nothing but the fabric of space-time itself.
But surely the story does not end here; the study of the cosmos has forced us to add two additional and hypothetical ingredients called dark matter and dark energy to this fantastic picture. No one knows what the next turn of events will bring and when.
In the end, the Force is a fascination to the fictional characters of the Star Wars universe and audiences alike but in a way it also reflects our own quest for understanding the forces of the world we live in. No doubt the future holds surprises that may change our view of the Force of the Star Wars universe and the forces of our own universe.