Dr. Ben Goldacre on Bad Science

More optical illusions

This is an interesting one as you may perceive the image spinning either clockwise or anti-clockwise. If you concentrate on the feet you may be able to make it appear to reverse its direction of spin. It was commonly believed that this depended on which side of the brain was being used, and subsequently people read into this a gender bias, but this has been proved to be false.

Here is another version where white outlines have been added to the figure. If you squint to obscure the outlines, you should be able to see both figures rotating in the same direction:

The spinning dancer is similar to the more familiar Necker-cube:

Depending on your point of focus, you can change the perspective of the large cube to make it appear as if it is either facing out of the page or into it.

Helen Keller

Helen Keller

Logical Thinking

Here is a nice exercise I´ve been using for ages (apologies to whoever I originally stole it from). The idea is to apply logic to a number of facts given in a story and then test the truth of your conclusions. After reading the story, mark each statement with 'T' if it is definitely true, 'F' if it is definitely false and '?' if there is insufficient information to make a decision. Once you have given an answer, don't go back and change it after reading the subsequent statements.

The old man had just turned off the lights in the shop and was preparing to lock up when a youth appeared and demanded money. The owner opened the cash register; the contents were grabbed, and the man ran away. The police were informed immediately.

1. A young man appeared after the lights had been turned off.
2. The old man was preparing to go home.
3. The robber demanded money.
4. Someone opened the cash register.
5. The robber demanded money from the owner.
6. The person who opened the cash register was a man.
7. The cash register contained money, but we are not told how much.
8. The gender of the owner was not revealed in the story.
9. The robber did not demand money.
10. After the young man grabbed the contents of the cash register, he ran away.
11. A young man appeared after the lights had been turned off.
12. The robber was a man.
13. The owner was a man.
14. The owner appeared and demanded money.
15. The man ran away after he had demanded money. 

If anyone wants to know my answers to this one, please let me know.

Coming up with a good knowledge issue

Here is some good advice about writing your knowledge issues. It's very important to read this and understand it, as knowledge issues have to form the central part of both the TOK presentation and essay: Understanding Knowledge Issues

Peter Popoff

Here is James Randi's take on the question I raised in my previous post - can faith healers like Peter Popoff be potentially dangerous?

James Randi

James Randi is a Canadian-American magician and sceptic. He is best known as a challenger of paranormal claims and pseudoscience. He began his magic career as "The Amazing Randi", but after retiring from the stage at age 60, he began investigating paranormal, occult, and supernatural claims, and has become best known as a "debunker" (He prefers not to use this term, and instead calls himself an "investigator"). He has written numerous books about pseudoscience, so-called psychics and those he regards as frauds and hoaxers.

Since the 1970s he has offered the "James Randi Educational Foundation Prize" (now standing at 1 million US dollars) to anyone who can prove they possess psychic powers under controlled testing. To date, nobody has been able to claim this reward. He has been the defendant in a number of high profile court cases (particularly involving Uri Geller), where various self-proclaimed psychics have claimed that he has defamed them (similarly to Simon Singh's case). He claims never to have paid any money in damages, although he does admit that defending himself has cost him a considerable sum of money over the years.

In this clip he talks about his writing, his TV appearances, his battles with Uri Geller and (particularly interestingly, I thought) his exposure as a fraud of American faith healer Peter Popoff.



It strikes me watching this that if people truly believe something, then very often, no amount of evidence to the contrary will dissuade them (belief can be stronger than knowledge). This is obvious when you consider that despite having had to admit his fraud and subsequently declaring bankruptcy, Peter Popoff is rebuilding his career, and judging by his new and flashy website, has rebuilt his following. Of course, it could be argued that Popoff is targeting a vulnerable section of society - and he is a powerful speaker in some ways. It has also been suggested to me that perhaps his "act" helped some people, confirmed their faith, and maybe in some ways healed them (sometimes physically). After all, the placebo effect is a powerful phenomena and not well understood. [Admittedly, I wrote this last part before I saw footage of one of Popoff's shows in which he encouraged members of his audience to come up to the stage and throw away their medication!]

It is interesting to watch some of Randi's earlier appearances on TV. In the following clip he meets psychic performer James Hydrick in what appears to be an 1980s version of the X-factor. Hydrick attempted to claim the Randi Foundation Prize, but mysteriously under controlled conditions his powers deserted him (as they often seem to do with psychic performers). Hydrick later admitted that his act was a simple trick that he learned in prison: