Thursday, August 2, 2012

The Difference Between A Theory And A Law

         Many times, I hear people say that something's not actually true because it is just a theory. Most people think of scientific theory as something that is above hypothesis but below fact, and they say a law is a fact. Others say that a theory will eventually develop into a fact once enough evidence has been gathered. Well, actually, all of those who think like that are misinterpreting the definition. 

This is priceless knowledge.
           A scientific theory is a comprehensive explanation of some aspect of nature that is supported by a vast body of evidence. A theory can only be considered a theory if and only if:

  • It makes falsifiable predictions with consistent accuracy across a broad area of scientific inquiry (such as mechanics).
  • It is well-supported by many independent strands of evidence, rather than a single foundation. This ensures that it is probably a good approximation, if not completely correct.
  • It is consistent with pre-existing theories and other experimental results. (Its predictions may differ slightly from pre-existing theories in cases where they are more accurate than before.)
  • It can be adapted and modified to account for new evidence as it is discovered, thus increasing its predictive capability over time.
  • It is among the most parsimonious explanations, sparing in proposed entities or explanations. (See Occam's razor. Since there is no generally accepted objective definition of parsimony, this is not a strict criterion, but some theories are much less economical than others.)

            Basically, a theory is not false unless proved otherwise. The first three criteria are the most important. You have the heliocentric theory, for example, which you can explain in a simple way: The Earth revolves around the sun. Never will a person find evidence that will contradict this.

It will NEVER change.
         A scientific law is formed with the scientific method, as is the theory. The law, though, is is a descriptive account of how nature acts upon certain condition. For example, the law of conservation of energy states that energy will neither be created nor destroyed, only transformed. This law will never change, as will the theory of gravity, which has its own set of laws, will never change. 

Time to teach the world their shit.
            Basically, this means that the theory of evolution, for example, is not a mere hypothesis and is actually a broad description supported by a wide array of facts. The Big Bang theory, until otherwise confirmed, is the explanation of how the universe came to be, with all the details possible explained. Plate tectonics theory, the earth shifts slowly with time, and this is something that is very well known and accepted by scientists everywhere. 

               So, the next time you're in an argument, don't be afraid to use a theory to back you up, and at the same time, don't wave someone else off because he/she uses a theory. Remember, laws form theories, basically, so it is still fact. Like Richard Dawkins said: