Humans succeed so well at using causes to achieve desired effects that David Hume’s assertion in 1739 still seems preposterous. He held that we cannot know the connection between cause and effect. We overlook the way we gain what knowledge we have. Success at particular efforts does not bring with it the knowledge of the necessary connection. Perhaps the shortest convincing proof is the observation that were we to know the connection we would be able to say how everything about us came about (Balzer, 1991).
Even in 1739 science had charted some causes remarkably well; Newton’s laws of momentum and his explanation of gravity had become old knowledge by then. Technology had made the industrial revolution a superb demonstration of man mastering cause and effect. How could a citizen of the 21st century accept Hume’s assertion? And yet over the dinner table the conversation had turned on our ignorance of what caused an effect that troubled her greatly. Her son had become depressed. Looking at the effect, could the Psychology Industry divine the cause and provide the cure? It certainly claims to do so and his psychiatrist was trying. The track record of psychiatry illustrates its failure. The amount of antidepressants dispensed over the past two decades had increased enormously at the same time that the diagnosis of depressive illness grew eightfold.
It took centuries for Hume’s reputation to grow. In his own time he had not escaped attention. He upset many. They branded his ideas as heresy at a time when burning at the stake remained the cure. Not until the 20th century did his ideas begin to exert their deserved influence. His take on economic policy influenced great makers and shakers such as the Iron Lady. His ideas have still more unrealised potential. I propose that his formulation of the connection between cause and effect be recognised as Hume’s law. It defines a limit that reason only too readily ignores.
Hume explained that we can only find that in each single instance an effect follows a cause, the sequence known as antecedent to consequent. Scientists hold to that sequence in experiment. Likewise our knowledge depends on the experience that the sequence imposes. Experience and experiment demand the “PRIORITY of time in the cause before the effect.”
Psychiatry and the law, indeed much common reason, readily ignores the principle. All who reason backwards from effects to discern the cause do so. Psychiatrists identify mental illness from effects (consequents), the complaints or symptoms that patients proffer. The law does the same when a court takes as sufficient proof of cause be the work done before the complaints appear. It reasons backwards from consequent to antecedent. In this way psychiatry and the law evade the discipline of experimental proof that observes Hume’s law. In doing so they succumb to current belief and prejudice. Antecedent prejudice impelled the outrageous conviction of Lindy Chamberlain and other innocents (see “The Disadvantage of Innocence” in Chap.5 of “Welcome to the Loony Bin“). It shapes a great many awards of compensation for pseudo-illness (also in Chap.5 see “Epidemic Pseudo-Illness”), thereby penalising employers and other innocents and undermining the economic health of the nation.
Docent
October 16, 2012 10:24 pmThe consequence of no certain cause and effect is that we live in a world of probabilities, where we cannot know exactly why things are occurring. The human brain does not deal or cope well with probabilities.
Douglas Hubbard in his book How to Measure Anything says physicians in particular are bad at dealing with probabilities, and bookies are better than executives. A bookie who then becomes a doctor may be better than a standard physician in determining the probability of a diagnosis where there are conflicting features to sort out. Hubbard makes the point that assigning probability is a learned behaviour and that mostly we are not trained in it.
So a patient comes to a doctor for a diagnosis and treatment. The doctor, poorly trained in probabilistic analysis is more certain of cause and effect because he does not understand his own limitations. This confidence makes the patient feel more comfortable that matters are under control, and for many common medical matters, that system works well. Some people call it the art of medicine.
Providing probabilistic presentation of cause and effect may work in a legal case but does not make a good bedside manner.
David Bell
October 22, 2012 9:11 pmHume’s law does not equate to “no certain cause and effect”. Rather it requires the exact opposite. Reality itself requires a certain connection between cause and effect. Without that certainty chaos would rule. David Hume steps in with a disconcerting blow to our vanity: we just cannot know the connection. An earthquake seems chaos, but we can know the cause with certainty. We can only know from careful observation the effect that follows an event. Knowing about a particular sequence even after detailed refined experiment does not mean we understand the intricacies of the mechanism that makes the connection. Hume does not invoke the weakness of our ability to keep in mind more than a few factors or to comprehend the uncertainty of probability. We have all that and more, but were we far better equipped in that direction we would still have that incapacity.
Doctors and judges, like the hoi poloi, do not recognise that. Give psychiatrists a pill to prescribe and they believe the utter nonsense that the manufacturer invents about its connections. Their ignorance of cause and effect makes them no more sensible than the hoi poloi, who venerate snake oil and other magic. Were we less confident about having an impossible ability, we would be fooled less often. Only in shared mutual ignorance do patient and doctor, client and lawyer, feel that matters are under control.