The Three Layer Causal Hierarchy [pdf]
web.cs.ucla.edu
The Three Layer Causal Hierarchy [pdf]
1–10 of 19 posts
Re: The Three Layer Causal Hierarchy [pdf]
#2Re: The Three Layer Causal Hierarchy [pdf]
#3I still don't know how to convince myself that causal relationships exist at all and that everything isn't just things like correlations, that would go into level 1 in this hierarchy if Pearl's.
Re: The Three Layer Causal Hierarchy [pdf]
#4I still don't know how to convince myself that causal relationships exist at all and that everything isn't just things like correlations, that would go into level 1 in this hierarchy if Pearl's.
I'll try...
Rain causes people to be wet. This implies that if we were to God-like stop the rain, people wouldn't be wet. But if we were to prevent people from being wet (by buying them an umbrella), that wouldn't stop the rain. This is not something you can infer from correlations alone.
Re: The Three Layer Causal Hierarchy [pdf]
#5I still don't know how to convince myself that causal relationships exist at all and that everything isn't just things like correlations, that would go into level 1 in this hierarchy if Pearl's.
I'll try... Rain causes people to be wet. This implies that if we were to God-like stop the rain, people wouldn't be wet. But if we were to prevent people from being wet (by buying them an umbrella), that wouldn't stop the rain. This is not something you can infer from correlations alone.
That's far too little logic to be a counterexample here. Rain correlates with a lot of things. If you were to stop all of those things, you could surely stop the rain as well. For instance, if rain is correlated with clouds, and you get rid of clouds, you'll get rid of rain. The fact is, there does not exist this thing you've called 'rain' that causes people to be wet and does nothing else relevant to your argument.
There's plenty of reason to believe that causal relationships are structural simplifications of correlative ones. We just don't have any great formalizations of them.
Re: The Three Layer Causal Hierarchy [pdf]
#6Earlier quoted context omitted.
I'll try... Rain causes people to be wet. This implies that if we were to God-like stop the rain, people wouldn't be wet. But if we were to prevent people from being wet (by buying them an umbrella), that wouldn't stop the rain. This is not something you can infer from correlations alone.
That's far too little logic to be a counterexample here. Rain correlates with a lot of things. If you were to stop all of those things , you could surely stop the rain as well. For instance, if rain is correlated with clouds, and you get rid of clouds, you'll get rid of rain. The fact is, there does not exist this thing you've called 'rain' that causes people to be wet and does nothing else relevant to your argument.…
What do you mean by structural simplifications?
Re: The Three Layer Causal Hierarchy [pdf]
#7This is really well-written, so I looked up the author, and no surprise it's Judea Pearl.
Re: The Three Layer Causal Hierarchy [pdf]
#8I still don't know how to convince myself that causal relationships exist at all and that everything isn't just things like correlations, that would go into level 1 in this hierarchy if Pearl's.
I'll try... Rain causes people to be wet. This implies that if we were to God-like stop the rain, people wouldn't be wet. But if we were to prevent people from being wet (by buying them an umbrella), that wouldn't stop the rain. This is not something you can infer from correlations alone.
The example I use is the sprinkler. Then you don't need God to intervene :)
Re: The Three Layer Causal Hierarchy [pdf]
#9I still don't know how to convince myself that causal relationships exist at all and that everything isn't just things like correlations, that would go into level 1 in this hierarchy if Pearl's.
Causal models are more powerful than associational models because they support interventions. That means that you can answer questions about what would happen if you were to "do(x)". This is different than asking the question about what would happen if you were to observe "x".
Let's look at a concrete example. Suppose in the real world, the gardener leaves the sprinkler off, the ground is dry.
If you were to observe that the sprinkler is on, you would deduce that the ground is wet. If you were to observe the wet ground, you would "abduce" that the sprinkler is on.
However, the interventional question: what if I were to turn on the sprinkler requires a causal model. In this case, the direction is critical. Turning on the sprinkler, wets the ground. Wetting the ground, does not turn on the sprinkler!
Causal models also have better invariants: unobserved causal children (say WetGround) leave their parents (say Sprinkler and Rain) independent. This is not necessarily true in an associational model. If Rain is correlated with WetGround is correlated with Sprinkler, then even when WetGround is unobserved, Rain gives you information about Sprinkler. Since our model has no other elements (such as a common cause between Sprinkler and Rain), then this transmission of information is totally wrong.
I couldn't tell if you were arguing against the utility of causal models or whether the real world exhibits causal relationships. If it's the latter, then it is ultimately a leap of faith based on our intuitive understanding of the world. All scientific experiments rely on the notion of cause and effect and interventional reasoning (experiments).
Re: The Three Layer Causal Hierarchy [pdf]
#10Earlier quoted context omitted.
I'll try... Rain causes people to be wet. This implies that if we were to God-like stop the rain, people wouldn't be wet. But if we were to prevent people from being wet (by buying them an umbrella), that wouldn't stop the rain. This is not something you can infer from correlations alone.
That's far too little logic to be a counterexample here. Rain correlates with a lot of things. If you were to stop all of those things , you could surely stop the rain as well. For instance, if rain is correlated with clouds, and you get rid of clouds, you'll get rid of rain. The fact is, there does not exist this thing you've called 'rain' that causes people to be wet and does nothing else relevant to your argument.…
We do have a great formalization of causality, which is Pearl's book.