What does “cause” mean?

T Clark

I’ve been thinking about causality a lot recently and the subject seems to have come up on a lot of threads. I thought it might make sense to figure out just what it means to call something the cause of something else. For the purposes of this discussion, I want to focus on physical causes of physical effects. I recognize that leaves out a lot of legitimate examples, but I want to keep it simple for now.

Aristotle writes about four types of cause - material, formal, efficient, and final. I’m pretty sure what I’m talking about is efficient cause. I’d rather not spend time walking through Aristotle’s classifications in this thread.

Here’s what Wikipedia says about philosophical causality:

Causality (also referred to as causation, or cause and effect) is influence by which one event, process, state, or object (a cause) contributes to the production of another event, process, state, or object (an effect) where the cause is partly responsible for the effect, and the effect is partly dependent on the cause. In general, a process has many causes, which are also said to be causal factors for it, and all lie in its past. An effect can in turn be a cause of, or causal factor for, many other effects, which all lie in its future. Some writers have held that causality is metaphysically prior to notions of time and space. — Wikipedia

Wikipedia also has something interesting to say about causality in physics. They claim that cause “...must be… ultimately reducible to fundamental interactions,” by which they mean the electromagnetic, gravitational, strong, and weak forces. That strikes me as true but not obvious.

I want to take a fairly detailed look at a very simple, actually cliched, example of physical causation - a moving billiard ball hitting a motionless one. For the purposes of this discussion, we won’t worry about what put the first ball in motion to begin with. More from Wikipedia:

Everyday objects do not actually touch each other; rather, contact forces are the result of the interactions of the electrons at or near the surfaces of the objects. The atoms in the two surfaces cannot penetrate one another without a large investment of energy because there is no low energy state for which the electron wavefunctions from the two surfaces overlap; thus no microscopic force is needed to prevent this penetration. On the more macroscopic level, such surfaces can be treated as a single object, and two bodies do not penetrate each other due to the stability of matter, — Wikipedia

From another source on the web:

The physics behind billiards (or the physics behind pool), in large part, involves collisions between billiard balls. When two billiard balls collide the collision is nearly elastic. An elastic collision is one in which the kinetic energy of the system is conserved before and after impact. Therefore, for simplicity one can assume that for collisions involving billiard balls, the collision is perfectly elastic.

For collisions between balls, momentum is always conserved (just like in any other collision). For a simplified case assuming no friction …we can combine this fact with the elastic-collision assumption to find the trajectory of two colliding billiard balls after impact. — Real World Physics Problems

So, when the two balls hit each other, by which we mean the electrons in the atoms near the surface of the balls repel each other, the collision is elastic. That means the force of the collision causes both balls to deform like springs. When they move back into their original positions, a force is exerted and energy is transferred from one ball to the other and the second ball starts to move.

The process I just described seems to me to be the essence of what we mean when we say that one physical event causes another one. As the text from Wikipedia noted, most events have more than one cause and may have many. I focused in as close as we can get to the point when energy was transferred from one object to the other in order to avoid an infinite regress of causes - the cue hits the ball, the muscles of the players arm and hand contract, the ligaments and tendons transfer motion from the muscles to bones….

Again - For this thread I’d like to focus just on the meaning of the words “cause” or “causalty,” not on any other philosophical issues. Also, as I noted, I’d like the focus to be on physical causes.

frank

Question answered. :up:

EugeneW

A physical cause is constituted by the various virtual fields, eternally and omnipresent in the vacuum, situated between charged particles. Real particles couple, by means of their charges, to these mediating fields. They cause changes in 4-momenta of the particles.

So the coupling of real particles to the virtual gauge particle fields causes other particles to change 4-momentum. Two real particles are needed at least. One particle coupling to the virtual field has a potential to cause.

Hanover

Again - For this thread I’d like to focus just on the meaning of the words “cause” or “causalty,” not on any other philosophical issues. Also, as I noted, I’d like the focus to be on physical causes. — T Clark

This seems more of a focus on the physics question of what causation is as opposed to the philosophical issues related to causation. The philosophical debate related to causation is: https://iep.utm.edu/causation/

For example, take Hume's comment "We have no other notion of cause and effect, but that of certain objects, which have always conjoin'd together, and which in all past instances have been found inseparable." This denies direct knowledge of causation and claims it's based upon an assumption that A causes B as opposed to A always seems correlated to B. Statistically speaking, the best you can say is that A is 100% correlated to B after n number of trials, but you can't ever say that A causes B.

So, you've spoken of causation, but you can't see the property of causation, as in your example, the bounce off one ball to the other. You can see the movement, but not the actual causation.

Shwah

↪T Clark

I think contemporary physics assumes energy and matter are what fundamentally cause things. In biology they assume some conception of life.

I think currently in physics they haven't put up a narrative as to what's a necessary component of cause and what's sufficient (such as quantum spin etc). It seems they're still trying to find more particles and trying to order them. I know string theory fell out of favor but quantum field theory has an argument for accounting for cause in quantum mechanics and general relativity (which both supplanted classical mechanics in manners of their own). In classical mechanics I believe kinetic energy was what caused things.

Manuel

All roads lead back to Hume on this one, with much merit of course, he gave the topic the fame it deserves and noted the massive issues involved.

So what is it causality? It's a good question and Hume would say that whatever it is, we can only see "constant conjunction", event B following from event A. There is surely more to causality than this, Hume unambiguously states, but that's not what we discover when we look at things happening in the world.

I'd add that whatever it is, is crucially determined by the creatures we are. We frame events so as to say that one follows the other, it's an open question if this is what nature does.

Sometimes it may. But we can't get out of our bodies to verify it.

EDIT: After reading the OP's request, I think the meaning of the word is more or less straightforward, we want to know what matter affects this other matter is such a way as to be able to state that one phenomena is intimately connected in the rising of another phenomena, which would not occur absent the preceding event.

T Clark

This seems more of a focus on the physics question of what causation is as opposed to the philosophical issues related to causation. — Hanover

I do, eventually, want to have a discussion about philosophical issues related to causation. I've already tried to have some of those discussions in various threads, but it's been a muddle. My plan is to make sure I am clear on what I mean by "causality" before I dig deeper.

Statistically speaking, the best you can say is that A is 100% correlated to B after n number of trials, but you can't ever say that A causes B. — Hanover

I think it goes further than that. Once you get past over-simplified situations like the billiard balls, it get's much more complicated. Most events have more than one and perhaps many causes. Events we call causes may not lead to events we call results 100% of the time. Being bitten by an infected deer tick causes Lyme disease, but not everyone who is bitten by an infected deer tick gets Lyme disease.

That's why I wanted to start out with something very simple.

Philosophim

In general, a process has many causes, which are also said to be causal factors for it, and all lie in its past. An effect can in turn be a cause of, or causal factor for, many other effects, which all lie in its future. Some writers have held that causality is metaphysically prior to notions of time and space. — T Clark

I wanted to quote this portion here as I think there is something unclear which needs to be sorted out. And aspect of causality may be time, but is not a necessary aspect of causality as it is often used.

For example, lets take a snap of a ball falling towards the Earth. We could say, "What causes the ball to be in that exact spot at that moment?" If we examined all of the forces on the ball, we could conclude that is the cause for the ball being there at that exact moment.

Causality first requires a state of identity. When I talk about the cue ball, am I necessarily talking about it down to the quark level? Likely not. Am I using the Earth's rotation or considering the slight speed up and slowdown as Earth orbits the sun through space? Likely not.

So an identity is set, as well as its scale. We might consider the cue ball, but ignore the subatomic level. Time is one of those identities that we can consider, but we set a scale for this as well.
Do we want to consider seconds? Nano-seconds? Months, years? The scale and identities we pick for our consideration all need to be considered.

As identities as well as scale can be varied, so can the term "causality". I just wanted to note that its very important to understand that time does not necessarily have to be an identity, or an identity at zero scale when considering causality in the snapshot of "Why is something in its current state?"

T Clark

I think currently in physics they haven't put up a narrative as to what's a necessary component of cause and what's sufficient (such as quantum spin etc). It seems they're still trying to find more particles and trying to order them. I know string theory fell out of favor but quantum field theory has an argument for accounting for cause in quantum mechanics and general relativity (which both supplanted classical mechanics in manners of their own). In classical mechanics I believe kinetic energy was what caused things. — Shwah

It is certainly true that I could have gone even deeper into the interactions of the billiard balls than I did. I could, theoretically, done an analysis using quantum mechanics. But where I drew the line makes sense to me.

Shwah

↪T Clark

Yeah I'm not sure what causes or how to account for kinetic energy to be honest. I gave a quick once-through about what the traits in quantum mechanics were. If I remember correctly, the difference between bosons and fermions was a De Morgan's law in dirac notation (which would intuit a logical reduction of physics) but irdr, it was over a year or two ago.

Hanover

Events we call causes may not lead to events we call results 100% of the time. Being bitten by an infected deer tick causes Lyme disease, but not everyone who is bitten by an infected deer tick gets Lyme disease. — T Clark

Causes always lead to events if we accept that every event has a cause, which is a basic metaphysical assumption. What you have identified isn't a metaphysical problem, but an epistemological one, meaning every cause doesn't have a predictable event, and by "predictable," I mean knowable. That we don't know whether you will contract Lyme's disease by the bite of an infected deer tick doesn't mean that there will not be an event that is caused by the bite of the infected deer tick, it just means you don't know what it will be.

As you increase the number of variables that can affect outcome, predictability decreases and is arguably eliminated, which is the foundation of chaos theory, but chaos theory doesn't suggest some events don't have causes.

EugeneW

Virtual particles, are the ultimate source of cause. They cause the real particle to come into existence, because of their influence on the vacuum (inflation). The gauge variety causes real particles to change momentum. More fundamental it can't get physically. Exactly how the coupling happens remains a mystery though.

T Clark

Causes always lead to events if we accept that every event has a cause, which is a basic metaphysical assumption. What you have identified isn't a metaphysical problem, but an epistemological one, meaning every cause doesn't have a predictable event, and by "predictable," I mean knowable. That we don't know whether you will contract Lyme's disease by the bite of an infected deer tick doesn't mean that there will not be an event that is caused by the bite of the infected deer tick, it just means you don't know what it will be. — Hanover

I've been thinking about the right way to respond to your post. Your points are good ones and are at the heart of the questions I want to get to eventually, which I think are metaphysical questions. I was going to try to avoid metaphysical issues in this discussion. Maybe that was an unrealistic hope.

I find this an unsatisfactory response to your post. I'll think some more and come back later.

T Clark

So an identity is set, as well as its scale. We might consider the cue ball, but ignore the subatomic level. Time is one of those identities that we can consider, but we set a scale for this as well.

Do we want to consider seconds? Nano-seconds? Months, years? The scale and identities we pick for our consideration all need to be considered. — Philosophim

I think you're exactly right, and that's why I wanted to look at the billiard ball example at a molecular level. I wanted to bring those framing, scaling issues out into the open so I could take a look at them. I think they are really important. The fact that we have to choose the scale and frame we are going to look at things at is also important.

Banno

↪T Clark

An excellent topic. Perhaps the breadth of the issue will become apparent as the discussion proceeds.

I'd suggest that the apparent way to cash out the notion that A caused B, where A and B are considered to be two distinct events, is something like that in each and every case in which A occurs, B follows. Implicit in this are modal considerations, the is, necessarily, A causes B if and only if every event A is followed by event B. We thus arrive at counterfactual theories of causation, which, despite having all the apparatus of possible world semantics at hand, fail to produce a coherent account.

A second try might be to soften "A causes B" from B always following A to B mostly following A; to treat causation as probable rather than certain. Hence the present preoccupation with causal models, which I am forced to admit show great promise in both their usefulness in practical application and to some extent their correspondence to our mundane notions of cause.

The alternative, for which I have great sympathy, is that the notion of cause cannot be cashed out in any great depth, to follow Hume in concluding that cause is more habit than physics.

A few things to note. Firstly, by taking the example of billiard balls, and especially the description of electron repulsion, as epitomising cause, we run the risk of falling into the common philosophical trap of reaching a wrong conclusion by limiting the examples we are considering.

And secondly, it is well worth noting that scientists, especially physicists, rarely if ever make use of the word "cause". It's philosophers who describe the work of scientists as finding causes. Scientists think of themselves as discovering how things are rather than what causes what. Try looking up "cause" in the index of a text in any science. If it were central to the scientific enterprise. one would expect more than one or two entries.

Tom Storm

↪Banno

Very nice. I've generally found that 'cause' is one of those words so beloved of apologists and their cosmological arguments. I rarely see it elsewhere, except when people are talking about wars...

Is cause something more like a necessary relationship?

Banno

'cause' is one of those words so beloved of apologists and their cosmological arguments. — Tom Storm

Oh, yes. A hangover of Aristotelian physics, used with ulterior motives.

Is cause something more like a necessary relationship? — Tom Storm

That's an important question. I agree that this is how it is often treated, as can be seen from some of the replies above, and the many other threads on the topic. The glory of

↪T Clark

's OP is that it dares ask the question "what is causation", and the answer is that it is not the necessary relationship so many suppose. Hence, David Lewis' brilliant analysis of the counterfactual (read necessary) nature of causation apparently ultimately fails.

(I find myself arguing with corrective text on this new laptop.)

Shwah

↪Banno

I'm not sure what science's lack of use of cause has to do with the situation. Evolution is still a theory as it has no causation narrative that is sufficient to explain what's happening.
In any case, what issue would you find with causation?

Tom Storm

Evolution is still a theory as it has no causation narrative that is sufficient to explain what's happening. — Shwah

As I understand it evolution was never about cause, it's about natural selection. Abiogenesis is about cause (or the lack thereof).

Shwah

↪Tom Storm

Sure natural selection's a cause. The question is "what cause dictates biological object x to become biological object y". People can erroneously assume it's due to "randomness" but that's explanatory for nobody.
Some people assume it's ad hoc or the explanation is due to "what survives".
Those are bad understandings of evolution and on the face of it seems like what's not happening. That being said, what *is* happening and with that how does that bring us to convergent evolution, divergent etc? We have nothing which's meaning formalizes this observation. Environment doesn't do enough and neither do predators. These variables influence it certainly but they're not sufficient explanations.

Edit: many different species live in a similar environment or have the same predators and can be vastly different. Genes looks like a good place to look but we currently have issues in science with "noise" (e.g. replicability issue) and now we're going to get more noise if web 3.0 gets big but it doesn't look popular because it's goofy. Probably a corporate-sponsored phase in technology to get more of our data.

Tom Storm

↪Shwah

With evolution the question is usually but what caused life? The evolutionary process is a piece of piss next to that question. Most people assume evolution has a cause narrative built into it, but it doesn't.

Shwah

↪Tom Storm

How would you describe evolution then without cause?

apokrisis

So, when the two balls hit each other, by which we mean the electrons in the atoms near the surface of the balls repel each other, the collision is elastic. That means the force of the collision causes both balls to deform like springs. When they move back into their original positions, a force is exerted and energy is transferred from one ball to the other and the second ball starts to move. — T Clark

You are hoping to project an intuitive notion of efficient cause onto the physical account - one where, as you say, you can ignore the rest of Aristotle's holistic account. Yet the physics will always let you down.

Even Newton's laws of motion say an elastic collision is the result of the ability of an inertial body to resist its acceleration as much as some impressed force might embody the capacity to accelerate it.

Every action is matched by the reciprocality of an equal and opposite reaction. So the causality is divided equally between the mover and the moved, it would seem.

And for free floating objects in space, this Galilean relativity becomes rather in your face. Who moves when the spaceman throws his space-wrench? Does the wrench move away from the throwing spaceman, or does the spaceman get propelled away by trying to budge his wrench?

Which inertial reference do you prefer? And how is that choice justified in fundamental law?

Efficient cause then really starts to get lost in the thickets when you shift up to actual relativity and its issues with simultaneity, or quantum mechanics and it nonlocalism and virtual particles.

Efficient cause can't explain anything all on its lonely ownsome. A holism which can provide the context is always going to be the other half of the story that completes the causal picture.

Tom Storm

↪Shwah

I was not talking about the cause of natural selection, I was talking about the fact that people always assume evolution is the secular person's first cause myth. That would be abiogenesis.

Shwah

↪Tom Storm

I was under the assumption the big bang was but I read it was developed by a priest and roundly rejected because it seemed too theistic lol.
I personally don't mind abiogenesis.

Tom Storm

↪Shwah

First cause of life - I should have said.

Banno

As I understand it evolution was never about cause, it's about natural selection. — Tom Storm

Yes, indeed. Science, and most other forms of explanation, simply do not make use of cause in the way some folk dogmatically suppose.

Which is as well, since it is so difficult to set out what cause is.

T Clark

Causes always lead to events if we accept that every event has a cause, which is a basic metaphysical assumption. What you have identified isn't a metaphysical problem, but an epistemological one, meaning every cause doesn't have a predictable event, and by "predictable," I mean knowable. That we don't know whether you will contract Lyme's disease by the bite of an infected deer tick doesn't mean that there will not be an event that is caused by the bite of the infected deer tick, it just means you don't know what it will be. — Hanover

I've thought about this some more and I don't think I have much more to add. Your point about causes having effects that aren't, and perhaps can't, be known is interesting. It's something I've thought about before without coming to a final conclusion. I'm not sure that is at the heart of what I'm calling the metaphysical issues with the idea of causality.

apokrisis

We thus arrive at counterfactual theories of causation, — Banno

Yep. The holism of the context.

A second try might be to soften "A causes B" from B always following A to B mostly following A; to treat causation as probable rather than certain. — Banno

Yep. The next step in understanding the causality of the context as the holism of global constraints.

So efficient/material cause are taken to speak to localised acts of construction. And the reciprocal to that - in the good old Aristotelean analysis everyone wants to ignore - is globalised states of constraint.

Constraints place limits on what is possible. But then what isn't prevented from being the case, is free to be the case. Indeed must be the case. Anything that isn't expressly forbidden is going to inevitably happen ... sooner or later, in unpredictable fashion.

The alternative, for which I have great sympathy, is that the notion of cause cannot be cashed out in any great depth, to follow Hume in concluding that cause is more habit than physics. — Banno

Yes and no. Even physics sees its laws as habits or emergent regularities. And being global constraints, they reciprocally define their own degrees of freedom. Global invariance is what grounds the kind of local variation that can freely exist - as by definition it isn't constrained.

And of course Peirce spelt that out explicitly as a metaphysics, a theory of probability, and a logic.

So yes, causality reduces to merely some notion of a habit. But no, this in fact cashes out our notions of causality in their greatest depth.

The good old Aristotelean analysis is yet again affirmed.

Try looking up "cause" in the index of a text in any science. If it were central to the scientific enterprise. one would expect more than one or two entries. — Banno

Perhaps you just don't recognise the rapid evolution of its definition in terms of measurables.

Once it was Newtonian forces that were shoving stuff about. Then it was Leibnizian vis viva or energy - where inertia resistance and forceful acceleration were unified as a measurable. Lagrangian mechanics was born. Eventually thermodynamics forced itself into the conversation and the cause of action become the production of entropy - a framing even more transparently Aristotelean.

So not sure where you get the idea that science doesn't talk about causality. That is what laws and differential equations are about - the global symmetries that define the holistic context and the local symmetry breakings that are the local causal actions you want to be able quantify.

Force, energy, entropy. These are concepts that make reality measurable with the context of their relevant levels of theory. And science has kept moving up the scales of abstraction to recover the general causal scheme of Aristotelean system science.

T Clark

Perhaps the breadth of the issue will become apparent as the discussion proceeds. — Banno

I think you're right. My hope to keep things focused on simple physical causes as a way to getting an understand what causality is probably isn't going to work out.

I'd suggest that the apparent way to cash out the notion that A caused B, where A and B are considered to be two distinct events, is something like that in each and every case in which A occurs, B follows. Implicit in this are modal considerations, the is, necessarily, A causes B if and only if every event A is followed by event B. We thus arrive at counterfactual theories of causation, which, despite having all the apparatus of possible world semantics at hand, fail to produce a coherent account. — Banno

I read through several paragraphs describing counterfactuals and causality. I think I understood what it was saying, but it seems much to complicated. That's why I wanted to start out with such a simple example. I guess my take, perhaps my prejudice, is that, if it's all that difficult, why not just get rid of the idea of causality completely and look at it some other way.

A second try might be to soften "A causes B" from B always following A to B mostly following A; to treat causation as probable rather than certain. Hence the present preoccupation with causal models, which I am forced to admit show great promise in both their usefulness in practical application and to some extent their correspondence to our mundane notions of cause. — Banno

I read through the section on probabilistic models of cause. Again, I think I understood it, but I think it's too complicated. Maybe this is my problem - at bottom, I've always seen causality as a complement to determinism. The ways of seeing things that you've described are much less rigid, I guess deterministic, than that, which is a good thing, but it seems like it loses whatever philosophical explanatory power it originally had. What value is there in loosey-goosey causality.

T Clark

The alternative, for which I have great sympathy, is that the notion of cause cannot be cashed out in any great depth, to follow Hume in concluding that cause is more habit than physics. — Banno

I neglected to respond to some of what you wrote.

As I noted, this view of cause is one I also find convincing. At this point my goal is finding a more formal and convincing argument than "seems to me."

A few things to note. Firstly, by taking the example of billiard balls, and especially the description of electron repulsion, as epitomising cause, we run the risk of falling into the common philosophical trap of reaching a wrong conclusion by limiting the examples we are considering. — Banno

Sure. I wanted to start with a very simple, familiar example of cause and then break it out in as much detail as I could think of. I found it helpful. It raised interesting questions with me. I guess I figure, if I can't figure this one out, I won't be able to get anywhere with more complex examples.

And secondly, it is well worth noting that scientists, especially physicists, rarely if ever make use of the word "cause". — Banno

In 1912, Bertrand Russell wrote an essay called "On the Notion of Cause" in which he makes a similar point.

What does “cause” mean?

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