The price of tea in China continues to cause my bike to rust.
Exposure to the elements continues to cause my bike to rust.

All the members in my household wake up around the same time.
By waking up, I cause everyone else in my household to wake up at around the same time.

Is it fair to say that the light switch SWITCHES the light between on and off? You SEE the light switch SWITCHING. Agree or disagree?

On a side note, you test the difference by controlling the variables.

And if you have built the system you have designed the causal relationship. But of course a true curmudgeon could claim that this isn't even proof enough, because the underlying principles of electrical potential and current must be explained and this infinitely regresses to ultimate causality. And a different curmudgeon could argue that all you've proved is the reliability of this correlation of circumstances. For instance, it's remarkable that a change in the light's state is always preceded by a change in the switch's position -- though it may be that it's the light that's responsible and it's retroactively changing the position of the switch.

I read a little about this outside of the forum yesterday. It seems this has been an ongoing issue for some time now. With no definite solution.

In summary, from what i read, It seems there are no true causes, only strong and weak correlations.

We know that those attributes are present together, claiming that molecular structure is what causes hardness is not a necessary claim. It suffices to say that molecular density ect. is always present with hardness so that if one is present, it is in general safe to assume the other.

I can't claim that nothing causes the rock to be hard nor can I claim that I know precisely what does at a totally fundamental level, I can only observe the relational patterns that occur and draw practical conclusions/predictions.

If this is causation:"that X is always present with Y and nothing else is necessarily present(and X is more fundamental than Y) means that X causes Y", then I agree that it is fine to say that the molecular structure of the rock causes it to be hard.

However, this does presuppose that there is no presently undetected Z(or ignores the possibility until the Z is detected and explored). That is fine, as it is more practical and sensible to only take into account what is known, however; it is important to keep the possibility of Z in the back of our minds, recognizing that causality is not an absolute known.

Ken has a point. If X causes Y and somehow we know that, it doesn't matter what causes X, insofar as we are looking for what directly causes Y.

Causation means that we can eliminate the possibility that the separate events could stand without the others or that some other event could proceed the given event(other possible causes).

But on the other hand, we know that limestone (and marble) are made out of calcium carbonate molecules, and to divide these molecules any further (i.e. into atoms or subatomic particles) means that you've 100% lost their specificity for limestone. For a rock made from a pure chemical, be it carbon for diamonds, calcium carbonate for limestone, silica for sandstone, whatever, the molecule is the final point of division that still has the properties of the object being studied.

Well, then doesnt it follow that if the unknown variable is not required in defining a rock, and that it is solely the molecules that define the properties of a rock, and since hardness is a property. The molecules are in fact what causes a rock to be hard.

Does this not establish a true cause?

While we're talking about curmudgeons, one might say that causality or correlation can apply only to unique sets of phenomena, as no phenomena ever truly recur;

Not if one asks the question why do these molecules cause the rock to be hard? You have to make your resolution even lower (i.e. more macroscopic) to address that question.

For example, elemental carbon occurs in two forms -- graphite and diamond. One is soft and opaque, and the other is extremely hard and transparent. So it's not simply the properties of elemental carbon alone, but rather the different ways in which they can be bound together. This is also true of liquid, solid, and gaseous H2O, in which it's not just the nature of this molecule alone that can provide the answer.

But surely it is a fallacy to say "We cannot prove that X causes Y, therefore X does not cause Y". Or "We cannot prove that causation exists, therefore causation does not exist".

And if induction is philosophically unsound, I want to know why it usually works.

I'm saying that causation is not possible to establish or verify to a 100% logical certainty (which in no way means that it doesn't exist).

If you want to know what the problem is with induction, here it is: There is no logical reason to think that something that happened before will happen again (because its a logical possibility, but not a logical necessity), only a practical one.

E.g. John notices that whenever X happens, Y always follows. After years of study and consistent empiric observation, John concludes that X causes Y. However, a few decades later, John II discovers that in rare instances when C is nearby, X does not cause Y, and also that sometimes Y appears without X. New observations are made, new processes are discovered, and the objects involved are defined more specifically, and so the relationship between X and Y becomes a correlation. Because all phenomena are infinitely complex, we can with equal reason level the charge of post hoc propter hoc error against any causal relationship; i.e. any claim that X causes Y will eventually be invalidated by the discovery of new aspects to X or Y, which reveal that the relationship is not so simple, and that C or Q are in fact involved in a more complex causation: and so on ad infinitum.

OK, I agree. But logical necessities are tautologies, and don't tell us anything about the world.

But why is the lack of a logical reason a problem? Since the practical reason is extremely strong, it should weigh very heavily in favour of causation, for philosophers as well as scientists. "Can we know for certain that causation exists?" (answer: no) is an epistemological question. "Does causation in fact exist?" is a separate, metaphysical, question.