Homeopathy isn't real, magnets, copper bracelets and crystals can't cure ailments and "psychic surgery" isn't an alternative to the real thing. Yet the public is encouraged to believe in such things because it doesn't understand how the real world works, according to "sceptic" Mr James Randi.
"What I am trying to do is make people into critical thinkers," Mr Randi stated last night during his Science Today lecture at the RDS, Ballsbridge, Dublin.
People didn't have to believe what he said, they only had to think critically, he added.
His talk to some 800 people was about science and pseudo-science in the new millennium.
Mr Randi worked for 45 years as a professional magician and illusionist and his ability to entertain a crowd was obvious last night.
He is internationally known for his questioning of exaggerated claims made by those who promote pseudo-science, but Mr Randi was at pains to clarify that he was not a "debunker".
Those seeking to debunk tend to have a negative attitude before they start.
He described himself rather as "an investigator of unusual claims", who was willing to keep an open mind on any issue until rigorous testing using scientific methods provided an answer.
Early on in the talk he described the differences between science and pseudo-science, but this represented a challenge.
"It should be easy enough but people have a big misunderstanding about science and what it is," he said.
People liked certainty but scientific data is under constant review and could change as new discoveries were made, he said.
"That is not the way with dogma, superstition and such. They don't invite questioning."
He took a critical view of homeopathy and other "quack medicines" and alternative approaches to medical treatment.
"They are such old forms of claptrap and so transparent when you start to understand what they are."
Homeopathy was often erroneously described as "dilute medicine" but the levels of dilution were such that no medicine actually remained. "They are taking nothing really," Mr Randi claimed.
He had a go at the media and its willingness to publish stories about pseudo-science. "The media is almost single-handedly responsible for the belief in the paranormal," he said.
He also repeated his standing offer to pay $1 million (€800,000) to "any person or persons" who can provide proof of a paranormal experience.
The claimants can set up their own tests, overseen by independent observers. There are preliminary tests and then more comprehensive tests in order to have a shot at the $1 million.
"No one has ever passed the preliminary tests yet," Mr Randi concluded.