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CausalityCausality, or causation, is the relationship between causes and effects. In common parlance, an event or state of affairs A is a cause of an event B if A is a reason that brings about the effect B. For instance, one might say "my pushing the accelerator caused the car to go faster." But this definition is somewhat circular; what does it then really mean to say that A is a reason that B occurs? An important question in philosophy and other fields is to clarify the relationship between causes and effects, as well as how (and even if!) causes can bring about effects.David Hume held that causes and effects are not real (or at least not knowable), but imagined by our mind to make sense of the observation that A often occurs together with or slightly before B. All we can observe are correlations, not causations.
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The establishing of cause and effect, even with this relaxed reading, isn'toriously difficult, expressed by the widely accepted statement "correlation doesn't imply causation". For instance, the observation that smokers have a dramatically increased lung cancer rate doesn't establish that smoking must be a cause of that increased cancer rate: maybe there exists a certain genetic defect which both causes cancer and a yearning for nicotine.
That said, under certain assumptions, parts of the causal structure among several variables can be learned from full covariance or case data by the techniques of Path analysis[?] and more generally, Bayesian networks[?]. Generally these inference algorithms search through the many possible causal structures among the variables, and remove ones which are strongly incompatible with the observed correlations. In general this leaves a set of possible causal relations, which should then be tested by designing appropriate experiemtns. If experimental data is already available, the algorithms can take advantage of that as well.
by degrees increase the unconscious action of her brain.
"One day I put two plates before her, one of soup, and the other of very
then I let her choose for herself, and she ate the plate of
appeared as if the only idea she had in her head.html">head was the desire for
her hands toward those that she liked, and took hold of them eagerly, and
try and teach her to come to the dining-room when the dinner bell rang.
a vague correlation was established between sound and taste, a
and consequently a sort of connection of ideas--if one can call that kind
carried my experiments further, and taught her, with much difficulty, to
hands, but I succeeded in making her remark the clockwork and the
not to have the bell rung for lunch, and everybody got up and went into
found great difficulty in making her learn to count the strokes.html">strokes. She ran
learned that all the strokes had not the same value as far as regarded
of the clock.html">clock.
"When I noticed that, I took care every day at twelve, and at six
the moment she was waiting for had arrived, and I soon noticed that she
often turned in her presence.
"She had understood! Perhaps I ought rather to say that she had grasped
sensation, of the time into her, just as is the case with carp, who
time.
"When once I had obtained that result all the clocks and watches in the
looking at them, listening to them, and in waiting for meal time, and
little Louis XVI clock that hung at the head of her bed having got out of
hands, waiting for it to strike ten, but when the hands passed the figure
that she sat down, no doubt overwhelmed by a feeling of violent emotion
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