Wikipedia:Reference desk/Archives/Science/2019 February 5

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February 5

Body System

Describe how internal structure of living organsims are different ? — Preceding unsigned comment added by 202.4.47.106 (talk) 03:46, 5 February 2019 (UTC)

Start by reading Body plan, and then proceed by clicking on the many linked articles. Graeme Bartlett (talk) 03:53, 5 February 2019 (UTC)

Why isn't low self-esteem considered a mental illness?

Given the number of self-help books on the topic, it seems odd that it isn't. But equally, I'm presuming that there's a good reason that it isn't.--Leon (talk) 16:19, 5 February 2019 (UTC)

I don't think "there's a good reason". In psychiatry defining what is illness, what is "just" disorder and what is not is a matter of constant debate and alteration. A good example is homosexuality. אילן שמעוני (talk) 17:04, 5 February 2019 (UTC)

Do we need to declare it a disease, start a awareness campaign, give it a special colored ribbon, set aside an awareness month, have athletes wear special logos, and funnel millions of dollars into the pockets of people who make all those ribbons, t-shirts, hats, etc...? 209.149.113.5 (talk) 18:07, 5 February 2019 (UTC)

See also Thomas Szasz "Szasz argued throughout his career that mental illness is a metaphor for human problems in living, and that mental illnesses are not "illnesses" in the sense that physical illnesses are; and that except for a few identifiable brain diseases, there are "neither biological or chemical tests nor biopsy or necropsy findings for verifying DSM diagnoses." Count Iblis (talk) 19:08, 5 February 2019 (UTC)

Yes, but the identification of a pathology is not necessary for one to presume the existence of a pathology. If a person suddenly develops explosive diarrhea, I don't need to identify the existence of the specific mechanism or cause of the explosive diarrhea to know two things 1) this is causing the person adverse outcomes and 2) this is something which, if it is in the ability of a medical professional to fix, they probably should. That's what we need here; the existence of a adverse health problem that reduces the quality of life of a person, and a demonstrated effective means to treat it. Knowing the pathology that causes the problem is certainly very useful, but it turns out not strictly necessary for many such outcomes. The adverse outcome presumes the pathology exists in the first place, even if we don't know the mechanism. There are lots of diseases for which we don't exactly know the causes, for example chronic fatigue syndrome or idiopathic pulmonary fibrosis, but which are still real illnesses in the sense that people have real, negative-quality-of-life-up-to-and-including-death problems created by these illnesses. Mental illnesses are no different; the lack of a known mechanism does not mean the lack of disease. It's a gap in our knowledge, not a gap in the reality of the illness. --Jayron32 19:44, 5 February 2019 (UTC)

You failed to understand Szasz's argument. He claimed that there is no underlying pathology at all and that what is defined as a mental illness is just an arbitrary collection of symptoms. Ruslik_Zero 21:01, 5 February 2019 (UTC)

He strikes me as being extraordinarily naïve. ←Baseball Bugs ^{What's up, Doc?} carrots→ 23:38, 5 February 2019 (UTC)

I think a few months denying freedom is a price well worth it for changing a person's life from ending up shouting strange things at people in the street and dying of the cold in a cardboard box under a bridge to being in a normal range of behavior with friends and a decent place to live. So I'm not at the far end of the libertarian spectrum like Szasz, bloody stupid idiot is the thought that comes to mind. Dmcq (talk) 11:51, 6 February 2019 (UTC)

Szasz does not speak from a place of knowledge. Not knowing that something is present is not the same thing as knowing it is absent. All brain behavior has a physical antecedent, unless Szasz is arguing for some sort of ethereal or non-corporeal "soul" which is unconnected to the physical world, and if that's the place he's arguing from, and that's the position also held by Iblis and yourself, I'm not sure this conversation has anything more to say, because we are operating in different universes. If, however, all brain activity is physical, then brain activity that causes a person suffering is by definition pathological, and as such, has a physical cause. Insofar as any medical professional has the role of decreasing suffering, it is certainly within the realm of the job of medicine (as a field) to treat mental illnesses. So, either all brain activity is physical, in which case suffering due to mental illness is a real pathology that can (hypothetically) be treated, or it isn't. The brain is no more magical an organ that a liver or a stomach, and as such, problems with its operation should be considered treatable. If something is a symptom, and that symptom causes suffering, it should be considered treatable. Unless, also, Szasz is arguing that suffering should be acknowledged and not be treated. Whatever his argument is, if it is what you claim it is, it suffers from either fantastic flaws in logic, or demonstratably incorrect assumptions, or some combination of both. --Jayron32 13:17, 6 February 2019 (UTC)

There can be people who suffer mentally, but in at least some cases this can also be due to society de-facto imposing a lifestyle on people that doesn't work out all that well. E.g. if hearing voices would have caused you to become a witch doctor in most of the 300,000 years that Homo Sapiens has existed, but only in the last few thousands years this is seen to be a problem and you need medication with a lot of side effects, then are you suffering because of a pathological brain condition or is society itself pathological in the way it deals with such people? Of course, some people can be so psychotic that they you could not reasonably function well in any society, and such cases would be good counterexamples. But there then has to be a plausible argument that in such cases there is likely something pathological in the way the brain is working in that person. In such cases one can agree that it would be unreasonable to invoke the fact that we don't know what exactly is wrong to argue that nothing is wrong. But the problem is that psychiatry has pseudo-scientific roots where on quite arbitrary grounds behavioral problems were considered to be pathological, take e.g. homosexuals in the past. Count Iblis (talk) 19:18, 6 February 2019 (UTC)

Yes, but to claim that "there's a few places we screwed up in the past" is not the same thing as saying "mental illness doesn't exist". That's a non-sequitur justification for claiming that there are no brain diseases because homosexuality was misclassified once. --Jayron32 00:49, 7 February 2019 (UTC)

Where do you get the idea that people who are counted mad in the west would be acceptable as witch doctors? I was treated by one once for an ear infection and he did a good job and certainly was not mad. Dmcq (talk) 14:24, 7 February 2019 (UTC)

Anyway as to the original question, why should 'low self-esteem' be considered an illness? People get on perfectly well with it and it can stop them doing silly things. Next one would be saying that pessimism is a disease. Dmcq (talk) 12:06, 6 February 2019 (UTC)

Given the high self-esteem of career politicians and career criminals (admittedly a fine line), maybe high self-esteem could be considered a mental illness. ←Baseball Bugs ^{What's up, Doc?} carrots→ 16:05, 6 February 2019 (UTC)

Given the plethora of literature on boosting self-esteem, including books that link it to depression and failure to achieve goals, one might conclude that it does cause suffering.--Leon (talk) 08:36, 7 February 2019 (UTC)

• Perhaps it may be better to think of low self esteem as a possible symptom of various mental health issues, like various Mood disorders. It would be like asking if a sneeze is a disease: not really; sometimes sneezing is a symptom of an illness like the common cold or influenza or hay fever, but sometimes you're just sneezing because you have dust in your nose. You wouldn't treat influenza the same way you'd treat hay fever, so the sneeze itself is not a disease with a treatment, really, it's an indicator of a possible illness that would need to be combined with other indicators before deciding if treatment is either desired or possible, and if so, what course of treatment to proceed with. Similarly, sometimes lowered self-esteem can be one of a spectrum of indicators for various mental illnesses, but by itself would not be an actual illness, and when occuring without other indicators, would not need any medical intervention. Just like a dusty nose can be cleared with an handkerchief or a kleenex without involving a medical doctor, it may be thought that, absent any other problems, there may not be any medical treatment for low self-esteem, which is a pretty non-specific and imprecise trait anyways. --Jayron32 14:33, 7 February 2019 (UTC)

Magnetic field cancellation material

HDD rare-earth magnets are fixed to some metallic plate, that somehow stops the magnetic effect. In the photo the magnet is red and plate is blue. Behind the blue plate iron (and other magnets) are not affected by the red magnet. How?

אילן שמעוני (talk) 17:00, 5 February 2019 (UTC)

The plate acts as a pole piece more than as shielding, although it will have a similar effect. It's a material (almost certainly iron or steel) which has a high magnetic permeability, i.e. if we make an analogy with elecric current we'd call this a good conductor. This doesn't "stop" the magnetic field (i.e. act as a barrier to it) but it does "short circuit" that field, by concentrating that field within the material rather than outside it, and so channeling the field to the ends of the material. Beyond the pole piece, the magnetic field is greatly reduced, because it has been moved elsewhere. Andy Dingley (talk) 17:08, 5 February 2019 (UTC)

Thanks! It all makes sense now. אילן שמעוני (talk) 17:38, 5 February 2019 (UTC)

Also see Mu-metal. --Guy Macon (talk) 12:58, 6 February 2019 (UTC)

A parallel idea is magnetic levitation. There an effective conductor (often superconductor) blocks the field lines so well that the magnet is held away from it even under the force of gravity. The way I put it (not sure it's entirely accurate) is that the magnet "sees its own reflection" and is repelled by it. In any case, the field doesn't pass beyond the surface eddy current that opposes it. Wnt (talk) 15:43, 7 February 2019 (UTC)