Hume couldn't find causality in reality it has no weight or extension or color properties of things we see in reality.
So he concluded that what we take to be cause and effect is basically a habit we have of associating certain events with earlier events.
If the association is seen often enough then we take it to be a causal association the earlier thing caused the later thing.
But the Hume could only describe that as a habit a human construction not an aspect of reality.
Now I'll be straight up I don't think that Hume denied causality he recognized cause and effect it's just that he couldn't fit it into a scheme where things in reality have properties like weight and color.
Fast forward a few centuries to our time to see what became of his line of inquiry. For a long time it looked like Hume was right the devil was in the details. when we look closely just why one event causes another it's very hard to say.
For instance what causes a rockslide on a mountain?
We know that one rock fell loose for some reason and collided with two rocks which fell loose and collided with two more rocks each etc.
But why did that first rock cause the avalanche?
Rocks fall all the time without causing avalanches. And I think that Hume was right the answer to that question is not to be found at the level of rocks; of things with weight, color, etc.
In contemporary thinking it's found at the level of fields. We've got familiar fields like the electromagnetic field or the gravity field. Physics is full of fields. And the idea of fields is starting to influence neuroscience.
Fields address Hume's problem in a way he might have found magical it seems that everything is connected.
What is a field?
At one level of abstraction a field has a number that is associated with each point in a space what that number is depends on some sort of mathematical function.
For instance; with a magnet the equations of electromagnetism define what the electromagnetic force is at any point in the space around it. You've seen that if you've ever played with a magnet and iron filings the filings line up in accord with what that field permits. If you move the magnet of course all the filings move too. Heh that "of course" was the problem that Hume was pointing to.
But now we have the idea of a field that makes that "of course" obvious; something Hume knew nothing about.
With a field we have the idea that everything in a space is interinfuential everything influences everything else.
If one part of the system changes the rest of the system HAS to change as well because the state of everything depends on the same underlying function.
How would we think of a skree slope in terms of a field? A skree slope is a slope of loose rocks lying one atop another. Where the rocks touch each other they apply pressure to each other so the slope is a field of pressures at points. When the pressures on any rock balance then that rock just has to stay where it is.
But say a rock is displaced then the field of pressure points changes some of the pressures rise and others diminish, and IF the pressures on a particular rock get out of balance then that rock will move. It has to it's being pushed by the pressure differential in the field of pressure points. It's not hard to imagine these changes in pressure points propagating through the field of pressure points with the imbalance sweeping through pile that was previously in equilibrium. And the whole pile slides downhill until a new equilibrium is established.
Fields in physics can be very hard to visualize Maxwell's 4 equations for electromagnetism may be very beautiful but I can't claim to have to have mastered them. But together they describe the electromagnetic field.
Let's return to that idea of the elements of a field being interinfluential. Rather than some parts being causes and other parts effects everything influences everything else all the time. So in Maxwell's equations you have 4 equations where the values of the variables vary. When any of the variables vary all of the other variables vary as well in just such a way that the 4 equations remain in balance. That is: the variables are interinfluential.
Maxwell's equations are quite amazing in that they are possible to construct at all. More amazing is that that set of equations accurately describes how a significant aspect of reality actually behaves.
I make no pretense that when I talk about the electromagnetic field or even the pressure field on a skree slope I am talking about fundamental reality.
Let's put it this way; Maxwell's equations gave us the epistemological tools we needed to work with electromagnetism as a property of reality. We know how to do the work.
But what is a field?
That's ontology and I don't know.
Why there are fields; why is it that reality works that way?
We talk glibly about things like 'force' but even Einstein wrestled with the idea of 'spooky action at a distance'.
It's an idea we can work with much like Hume could work with cause and effect without yet fully grokking just how it can be. But I think that with fields we have moved a long way towards understanding what causality is and why we don't have to worry about it not having a color or weight.
Causality is just the bald fact that on very many levels nothing happens without effecting everything else.
What do you think?