You can't actually be sure you're observing the effects of something unless you have another group that is essentially the same but not actually being exposed to that something.

Such a basic principle, but also of crucial importance.

I suspect that anyone who's ever been involved in an argument about science on the internet will have seen the line "correlation does not imply causation".

That's true as far as it goes. But correlation *does* imply mutual causation. if I see that A and B are correlated then I can confidently conclude that either

A is causing B
B is causing A
Some third factor C is causing both A and B

The key point of a control group is that you assign people to it or the study group randomly.

Suppose that I conjecture that B is causing A. If I randomly assign people to a study group and a control group, and give them different levels of B, then I fully understand the causation of variation in B - it's caused entirely by my coin-flip! This means that A can't be causing it, and nor can any third factors. So if B and A remain correlated then it must be because B is directly causing A.

But if I assign to the control and the study group using some non-random criteria C, I can't be certain that C isn't causing A.

Also many times studies aren't done for political or some other stupid reason because it interferes with a belief system. There are many people who have improved their health by following a diet that is held in horror by the medical profession and the USDA. People with type 2 diabetes and others have seen great results by eating few carbohydrates and more fats (animal and plant). Sugars have gone down, LDL cholesterol down HDL cholesterol up, triglycerides down, a lose of weight and improved blood pressure. Yet the dietitians, PCP and endocrinologists hold to the high carb low fat diet mantra like it is ordained from heaven.

This is just an example of the obdurate attitude by established medical people. Yes it is anecdotal but that doesn't mean that it should be dismissed out of hand. Saying it is false because it is anecdotal is false reasoning. It must be proven false by true studies that are double blind. Why not. By the way, This diet was what extended the life of type 1 diabetics before the discovery of insulin. It did not give them long life but helped them to live longer.

Those are my concerns. There seems to be a real dearth of innovative and imaginative thinking in the "scientific" world these days. I suspect that is because most studies are funded for a purpose instead of being done to increase human knowledge.

You are just making baseless statements without justification.

adulterated by greed and politics; research that desires to increase our knowledge regardless of the repercussions. This is probably still true in astronomy because they have figured a way to turn that into obscene profiteering.

I suppose I am a cynical old man. In my career I worked for NASA, helped out with the beginnings of NOAA, am the son of a scientist mother. The changes I've witness over the years in research have not been inspiring. Funding is cut and worst research is expected to pay for itself. Researchers scramble for grants like congress critters working the lobbyists for money.

Back to my example about diabetes research; where is the work being done to determine the underlying causes of metabolic disorders? The pharmaceuticals are constantly churning out new iterations of drugs that over more hyperbole than results. Some are down right dangerous but they all have one thing in common, they make the firms billions of $s. The same is true in a lot of other medical disorders. Older drugs that are helpful in alleviating depression and other mental disorders are being abandoned for newer drugs that are often no better and often worse. Again there is a common denominator, the new drugs make billions for the companies the old drugs are cheep.

I mentioned NASA and NOAA, I also worked in product development in R&D labs. The work I did is no longer an option. Those companies are like the drug companies that no longer do much new research. What they do is to reconfigure old designs into new flashy packaging with the added bonus to them of planned obsolescence.

It is true that scientific research has never been completely uncontaminated by financial and political influence, but it was more balanced; just the same with print, audio and video news reporting. There was a time journalists did their best to be unbiased unless writing editorial or on the OpEd page. Now it's all OpEd.

You may think this is unrelated to the original topic, but it is all the same. The truth is sweep under the proverbial rug and the flimflam artists rule the broom.

With a classic fallacy or two tossed in for good measure.

I'm not that easy.

So this fruitless discussion is at an end.

There needs to be a bigger, bold discussion, but not on here. It needs to be done where people can submit founded information, where they can cross the media, where exposes' are welcome, and investigative reporting steps in to alert us. Isn't that part of democracy? As long as a drug company can sell you a pill, they sure won't accept that "anecdotally" a teaspoon of baking soda is more effective and safer? If taking vitamin D would cut your risk of cancer, that too,could cut into profits. The media is no longer a source for the people, one only need to see who sponsors your chosen news source to know who really owns us.

you're right!