All this talk about hypotheses brings us around to theories. A theory is not just a guess. A theory is a group of related hypotheses that have been repeatedly validated by observation and survived all attempts to falsify. The strongest theories have hundreds of independent hypotheses with thousands of confirming experiments.
There is no minimum number of hypotheses or validations or falsification attempts needed to be a theory. There are just weaker and stronger theories. My cat color theory is really weak.
One hypothesis often leads to more. My hypothesis, that cats are either orange or grey, led me to another educated guess: a cat’s fur color was camouflage to help it hunt and hide.
This new hypothesis makes some bold predictions. If their fur was camouflage then:
- Wild orange cats should live in a place where the land is orange colored, maybe the prairie wheat fields of Kansas?
- Wild grey cats should live in grey places. Maybe the foggy Smokey Mountains of Tennessee?
- There might be green cats living in jungles and rain forests.
- There might even be white cats living in Canada near the North Pole.
- If we dig in lands that used to be orange or grey, we should find cat bones.
All five predictions can be tested. And the hypothesis can be falsified several ways. For example, if we find wild grey cats in Kansas, my guess is wrong.
Now lets assume that prediction No. 1 and No. 2 get verified. Wild orange cats are found in Kansas and grey ones in Tennessee. I now have a theory of cat fur colors. Cats are orange or grey. Their color is camouflage for where they lived in the wild.
My theory makes some predictions that still need to validated, and that’s OK, and of course it can be falsified at any time.
Scientists build on each other’s work and challenge one another all the time. One scientist might add to my theory with a new hypothesis: maybe black cats live in dark caves. Another scientist might propose a rival theory: a cat’s fur color is based on the color of food they eat. The experiments and observations will decide which, if any one, is right.
OK, let’s forget about cats for a minute and look at a real theory that truly changed the world.
Back in the 1800s scientists knew a bit about electricity and magnets and sunlight, three completely different topics. For instance, they knew that:
- electricity (like lightning) could flow through copper wires
- compass magnets pointed North
- sunlight travelled roughly 186,000 miles per second, and
- a prism could turn sunlight into a rainbow of colors.
They also knew two weird things but did not understand why:
- flowing electricity caused nearby compass needles to point towards the wire, not North.
- Moving magnets caused electricity to flow through nearby copper wires.
Then Scottish scientist James Maxwell figured out that electricity and magnetism also travelled at almost 186,000 miles per second similar to light. And then he had this crazy idea, an educated guess, that electricity and magnets and sunlight were really the same thing: electromagnetism. His crazy theory was eventually validated by thousands of experiments and survived hundreds of attempts to falsify it. It is one of the most successful theories ever made.
Electromagnetic Theory has led to the creation of electric generators, light bulbs, automobiles, telephones, computers, televisions, radios and lasers. It also inspired Albert Einstein to propose his theories of relativity.
(Please Note: The cat color idea discussed here is complete fiction. It is meant to illustrate how scientists think, not to be real science. Cats come in lots of colors and I don’t know why. A good scientist should always first research a topic thoroughly, perhaps in the library or on the Internet, before making “educated guesses”. But remember, I was just a little kid when I got my cat, Tang.)
Fun Phineas Facts
Some people criticize science saying “you don’t know anything for certain, you are constantly changing your mind”. This is true! But it is science’s biggest strength, not a flaw. Scientists are always questioning things, looking for better answers, and accepting the new evidence.
This also doesn’t mean that there are no facts in science. The theory of how gravity works does not change the fact that there is this thing called gravity and if you throw a water balloon up in the air, it’s going to come down and go splat. Electricity creates magnets; magnets create electricity. That’s a fact.