To paraphrase Lincoln, you can't fool all the scientists and engineers all of the time. But a clever charlatan can certainly fool some of them much of the time, as Britain's celebrated mystery man of science - Daedalus - has discovered in exhibiting his fake perpetual-motion machines.
Science consultant David Jones, his identity concealed by his pseudonym, regularly amuses readers of New Scientist by outlining Daedalus' semiplausible inventions. There is, for example, the negative sound generator. It subtracts the right frequencies from a background of white noise to make meaningful patterns the ear should be able to hear. It would be a little like seeing a dark pattern etched out of a white background.
Three years ago Jones launched a more open career as what he calls ''a self-confessed fraud and charlatan.'' He began exhibiting a perpetual-motion machine at certain scientific and engineering meetings. Visitors were challenged to explain how it worked. He recently reported his experience with this in New Scientist.
A perpetual-motion machine is a mechanism that would run forever with no source of energy. This is impossible, because it would violate the conservation-of-energy law. The Daedalus machines have a concealed driving mechanism. But their main feature is an abundance of false clues. Jones explains that, as with any conjuring trick, ''the secret is not to conceal, but to confuse.'' So he complicates his machines with what he describes as ''a number of cunning distractions, each designed to lead the scientific mind along one or other of several false trails.''
Jones says his main conclusion from the attempts of scientists and engineers to understand his machine is that these professionals ''are remarkably gullible, and easily taken in by conjuring tricks.'' He lays this to the nature of their work. Scientists are used to deciphering nature, which may be subtle but is not deliberately deceptive. Likewise, the goal of an engineer is to produce something that works and that other people can use. It is not to deceive.
Jones observes that ''such honest individuals clearly found it hard to conceive of a machine of which large sections serve no useful purpose, and struggled to dream up mechanisms that incorporated all my decorations.'' One scientist, for example, convinced himself that some painted metal strips were photovoltaic cells which powered the machine.
Jones also noticed that some experts were rather inflexible in their approach to deciphering his machines. He considers this to be ''a vice of successful, establishment minds.'' Having settled on a theory, such thinkers ''seized on all the evidence for it, and were strangely oblivious of evidence against it,'' he says.
This is not the first time these weaknesses of the scientific and engineering community have been noted. Scientists have a reputation for being taken in by frauds claiming psychic powers. And the resistance of establishment thinking to innovation is legendary.
Science historian Norris S. Hether-ington recently pointed out a number of cases where senior scientists silenced junior colleagues who were pointing out discrepancies in orthodox theories or challenging prominent scientists too sharply. Reviewing these instances in Nature, Hetherington notes that ''the demonstrable influence of subjective elements into what has been widely supposed to be an objective and autonomous enterprise'' could undermine scientific authority.
The experience of Daedalus and his perpetual-motion machines is amusing. Yet it is also a warning. These peccadillos of scientists and engineers can mislead their judgment in more serious matters, especially when these are infused with political controversy. Thus one should take the pronouncement of experts with a healthy skepticism on such issues as nuclear power plant safety or arms control, where vested interests are only too eager to manipulate the technicians.
Meanwhile, if you want to take up Daedalus' challenge and can get to Toronto, his latest machine should soon be on show at the Ontario Science Center. There it is expected to run for five years - if not perpetually.