Here are some examples of successful science:
Some theories have proved their worth and have survived all attacks for a long time. No one attempts to disprove them anymore because this would be a waste of time. Examples for such theories are that matter is made of atoms, that color is tied to the wavelength of light, that people and apes have common ancestors, that adding carbon dioxide and methane to the atmosphere produces warming, that continents move at a rate of about an inch a year and that the sun is a nuclear furnace converting hydrogen into helium (as do most other stars). These theories, in sequence, were invented 2000 years ago, 350 years ago, 150 years ago, 100 years ago, 80 years ago and 60 years ago. They have become fundamental to doing science. Saying that any one of these things is not so will not identify you as a skeptic (worth listening to), but as one who has missed class (worth ignoring).
- The hypothesis that the seafloor renews itself all the time (Harry Hess, 1962) could readily be falsified if we found rocks older than 200 million years on the deep-sea floor. More than a thousand holes were drilled since Hess suggested this, and no one ever found anything older than about 150 million years. Good guess.
- The hypothesis that mammoths and rhinos died out in Eurasia with the advent
of the Great Ice Age (Louis Agassiz,
1866) was disproved when it was shown that the extinction occurred at the
end rather than at the onset of the ice ages in the northern hemisphere. Tough
- The hypothesis that Mars is inhabited (Percival Lowell, 1908) was shown to be highly unlikely when it was discovered that Mars has a very thin atmosphere, and was made untenable by the close-up pictures of the Mariner and Viking spacecraft in the 1960s and 1970s, showing that the structures Lowell had seen were natural features, not artificial ones. Nice try, but no cigar.
- The hypothesis that the Moon was once torn from Earth (suggested by George Darwin, son of Charles) was out of favor but received support from the finding, based on direct sampling by the Apollo 11 mission (1969), that rocks from the Moon are much like those in Earth's mantle. Hmmm…could be true after all; perhaps a collision was responsible (an idea proposed by William Hartmann in 1974).
In summary, "science" is about making conjectures to explain what we observe, and demolishing as many conjectures as possible while obtaining ever better explanations. Although scientists have "opinions" in their field of expertise, these are founded on observation and theory rather than on "belief", and they remain open to challenge. Traditional "belief", which is the certain knowledge that something is just so, based on being told when young or based on special individual insight, remains important in human affairs and cannot be replaced by science. Such belief allows us to live together as civilized beings. Ethical behavior, for example, is largely a result of belief rather than of science: Observation tells us that the sun shines equally upon the just and the unjust, so a preference for being just must come from ethical principles rather than from scientific analysis.