Causality is existential for all the natural sciences and especially for physics.
Causality is magic. It is magic because why it should be so is inexplicable.
The most fundamental, enabling assumption for all the natural sciences is that identical causes lead to identical effects. The corollary that non-identical events are proof that the causes were not identical is also unquestioned – and unquestionable – for the scientific method. (However it is permitted that different causes may produce effects which are identical). Modern physics and relativity constrain causality. Cause and effect is restricted to the past and future light cones for any event. But this, in itself, implies a region (undefinable) where causality does not apply and does not even try to address why the magic that is causality exists.
Causality means that an effect cannot occur from a cause that is not in the back (past) light cone of that event. Similarly, a cause cannot have an effect outside its front (future) light cone.
In special and general relativity, a light cone is the path that a flash of light, emanating from a single event (localized to a single point in space and a single moment in time) and traveling in all directions, would take through spacetime.
Being a fundamental assumption, it is not possible for the sciences and the scientific method to address why the assumption of causality exists. The First Cause problem is declared to be uninteresting to science just because it cannot be addressed. Allowing the problem would place all of science within a paradox. If everything has to have a cause then there must be a First Cause. If some things do not need to have a cause then there can be no certainty that anything is the cause of anything else.
The First Cause problem is what actually unifies science and philosophy and theology and religions. None have – or can have – an answer. They just use different labels for the undeniable magic. It has been debated since ancient times but I like the way Bertrand Russel expresses it.
Bertrand Russel- Why I am not a Christian
Perhaps the simplest and easiest to understand is the argument of the First Cause. (It is maintained that everything we see in this world has a cause, and as you go back in the chain of causes further and further you must come to a First Cause, and to that First Cause you give the name of God). That argument, I suppose, does not carry very much weight nowadays, because, in the first place, cause is not quite what it used to be. The philosophers and the men of science have got going on cause, and it has not anything like the vitality it used to have; but, apart from that, you can see that the argument that there must be a First Cause is one that cannot have any validity. I may say that when I was a young man and was debating these questions very seriously in my mind, I for a long time accepted the argument of the First Cause, until one day, at the age of eighteen, I read John Stuart Mill’s Autobiography, and I there found this sentence: ‘My father taught me that the question, “Who made me?” cannot be answered, since it immediately suggests the further question, “Who made God?” ’ That very simple sentence showed me, as I still think, the fallacy in the argument of the First Cause. If everything must have a cause, then God must have a cause. If there can be anything without a cause, it may just as well be the world as God, so that there cannot be any validity in that argument. It is exactly of the same nature as the Hindu’s view, that the world rested upon an elephant and the elephant rested upon a tortoise; and when they said, ‘How about the tortoise?’ the Indian said, ‘Suppose we change the subject.’ The argument is really no better than that. There is no reason why the world could not have come into being without a cause; nor, on the other hand, is there any reason why it should not have always existed. There is no reason to suppose that the world had a beginning at all. The idea that things must have a beginning is really due to the poverty of our imagination. Therefore, perhaps, I need not waste any more time upon the argument about the First Cause.
Russel is wise not to debate it further because penetrating the wall of the unknowable is a futile exercise. It is in the realm of magic.
Leibnitz’s formulation of the Principle of Sufficient Reason is only a formal description of Causality and defines the limits of empiricism and the scientific method. It cannot, however, penetrate the First Cause Problem.
Principle of Sufficient Reason
The Principle of Sufficient Reason stipulates that everything must have a reason, cause, or ground.
This is often formulated as:
- For every entity X, if X exists, then there is a sufficient explanation for why X exists.
- For every event E, if E occurs, then there is a sufficient explanation for why E occurs.
- For every proposition P, if P is true, then there is a sufficient explanation for why P is true.
This is a stipulation, a statement of an assumption. But it is no explanation.
The conclusions I draw are that:
- Science is limited to where causality occurs.
- Physics admits causality is constrained by past and future light cones.
- Physics therefore admits that what lies outside the past and future light cones is unknowable.
- Causality is magic.
- All science depends upon magic.
Tags: Causality, First Cause, Magic