How do natural sciences prove causation?

post by Kongo Landwalker (kongo-landwalker) · 2024-06-28T11:58:49.643Z · LW · GW · No comments

This is a question post.

Contents

  Answers
    9 Dagon
    6 philip_b
    3 JoeTheUser
None
No comments

Let's say we have 2 phenomena, A and B, each can be a value of 0 or 1, and we observe, that for them implication table A=>B is always true. (Third column represents whether the combinations of events can happen or cannot.) A B A=>B

0 0 1

0 1 1

1 0 0

1 1 1

Thing we see is that combination A=1 and B=0 almost never happens, and three other combinations can happen. But how can we be sure, that it is not some kind of third event, which influences both of those to output those combinations of values?

What if the table is like this, based on &?

0 0 0

0 1 0

1 0 0

1 1 1

If at least one of events (any) happens, then the second happens too. How this relation would be called?

How many tables (of the 16) there are which could potentially represent causation? For example,

000

010

101

111

Given a table in this format (or just a string representing the third column), what a person would do next to test whether events influence one another or are both defined by a third? Does the further approach even depend on a type of table? (I expect it will not, as everything would be observed in frequencies)

Is it like an cycle, where one makes an assumption "what if they both are defined by event C" and then shows there is no correlation with C, and repeats for many other possible C's? But then it looks it would not be possible to exhaust all possible C's.

Answers

answer by Dagon · 2024-06-28T13:31:47.066Z · LW(p) · GW(p)

I have 3 answers, depending on what level you're asking:

  1. There's no such thing as causation, and maybe not even time and change.  Everything was determined in the initial configuration of quantum waveforms in the distant past of your lightcone.  The experience of time and change is just a side-effect of your embeddedness in this giant static many-dimensional universe.
  2. Causation cannot be determined by pure observation.  It can be inferred pretty strongly, if there are "natural experiments" that isolate A and B, and A happens before B and we can't find anything else that might be upstream causes.  Yes, absence of evidence, in the bayesean sense, is evidence of absence.
  3. Causation can be pretty strongly determined by directed experiment.  The experimenter IS the upstream cause of the change, and carefully manipulates A in ways that other causal effects are isolated from what happens to B.

Remember, causality (like everything about undersanding the world) is a model - it lives in the map, not the territory.  All models are wrong, some models are useful.  This one turns out VERY useful in making your way through the world, and in understanding likely chains of future events.

answer by philip_b · 2024-06-28T12:09:14.944Z · LW(p) · GW(p)

To check if A causes B, you can check what happens when you intervene and modify A, and also what happens when you intervene and modify B. That's not always possible though. You can consult "Causality: Models, Reasoning, and Inference" by Pearl for more details.

answer by JoeTheUser · 2024-06-29T04:47:02.056Z · LW(p) · GW(p)

This is an interesting question even though I'd want to reframe it to answer it. I'd see the question as a reasonable response to the standard refrain in science; "causation does not imply correlation." That is, "well, what does imply causation, huh?" is natural response to that. And here, I think scientists tend reply with either crickets or "you can not prove causation, what are you talking about". 

Those responses seem satisfying. I'm not a scientist through I've "worked in science" occasionally and I have at times tried to come up with a real answer to this "what does prove causation" question. As a first step I'd note that science does not "prove" things but merely finds more and more plausible models. The more substantial answer, however, is that the plausible models are a combination of the existing scientific models and common sense understandings of the world and data. 

A standard (negative) example is the situation where someone found a correlation between stock prices and sunspots. Basically not going to be pursued as a theory or causation because no one has a plausible reason why the two things should be related. Data isn't enough, you need a reason the data matter. This is often also expressed as "extraordinary claims require extraordinary evidence" (which also isn't explained enough as far as I can tell). 

Basically, this is saying natural science's idea of causation rests on one big materialistic model of the world rather than scientists chasing data sets and then finding correlation between them (among other things, the world is full of data and given some data set, if you search far enough, you'll find another one with a spurious correlation to it). Still, the opposite idea, that science  is just about finding data correlation,  is quite common. Classical "logical positivism" is often simplified as this, notably. 

Moreover, this is about the "hard" sciences - physics, chemistry, biology and etc. Experimental psychology is much more about chasing correlated and I'd say that's why much it amounts to bald pseudoscience. 

No comments

Comments sorted by top scores.