It’s Not “Just A Theory.”

The definition of the word theory according to Merriam-Webster’s dictionary is as follows:

  1. The analysis of a set of facts in their relation to one another.
  2. Abstract thought: speculation.
  3. The general or abstract principles of a body of fact, a science, or an art.
  4. A: a belief, policy, or procedure proposed or followed as the basis of an action <her method is based on the theory that all children want to learn> B: an ideal or hypothetical set of facts, principles, or circumstances – often used in the phrase in theory <in theory, we have always advocated freedom for all.
  1. a plausible or scientifically acceptable general principle or body of principles offered to explain a phenomena <the wave theory of light>
  2. A: a hypothesis assumed for the sake of argument or investigation. B: an unproven assumption: conjecture C: a body of theorems presenting a concise systematic view of a subject <theory of equations>


That’s quite a bit to take in, but like almost every word in the English language we reveal a different meaning for the same word within different context, which is why English is one of the harder languages to learn. With this in mind, the use of the word in scientific terms differs greatly than that of its everyday use by an average guy like me.

For example the definition of theory takes a much different meaning when in relation to science. A scientific theory as defined by the United States National Academy of Sciences is as follows:

The formal scientific definition of theory is quite different from the everyday meaning of the word. It refers to a comprehensive explanation of some aspect of nature that is supported by a vast body of evidence. Many scientific theories are so well established that no new evidence is likely to alter them substantially. For example, no new evidence will demonstrate that the Earth does not orbit around the sun (heliocentric theory), or that living things are not made of cells (cell theory), that matter is not composed of atoms, or that the surface of the Earth is not divided into solid plates that have moved over geological timescales (the theory of plate tectonics). One of the most useful properties of scientific theories is that they can be used to make predictions about natural events or phenomena that have not yet been observed.


And with regards to that last part, all of the most well known theories are still proving accurate well beyond their inception. Now lets take my use of the word theory in everyday life. For instance while I’m standing at the gas pump cringing at the sight of $4.07 from the neon sign at my gas station versus the price I see later ($3.70) that day as I’m heading to work, I may throw out a thought such as, ‘If the prices are so different one place to the next, then in theory, we should just lower the price to anything we want?!’ I’d think this out of ignorance of how the overall system works, which would make my statement based off of conjecture or mere speculation. I’m not going to sit down a try to prove my theory on how the oil industry operates their pricing systems though I might do later research once the work day is over. In any case this is an example that falls under the abstract or unproven assumption context of the word. Call my gas comments, “just a theory,” and you’d be 100% correct.

Science, of course, does not operate that way and can’t operate that way because successful scientific theories purposed within scientific communities require reproducible extensive testing and peer review to then prove or illustrate their hypothesis. For example, I could say 1+1=3 but peer review and testing will prove otherwise. This is what science does in our culture. There is no claim to ultimate knowledge, which is not physically reproducible by peer review.

Lets look at some of the major scientific theories and how they relate to everyday life…

HELIOCENTRIC THEORY: (or Copernican Model)


This theory explains the fact that all of the planets within our solar system orbit around the Sun, the moon orbits the Earth, and that the Earth rotates rather than stars orbiting it. His philosophical hypothesis moved to a scientific theory (as we understand it’s context today) using geometry.

Before Nicolaus Copernicus published his idea in 1543, the general thought was that the Earth was the center of the solar system, that the other heavenly bodies were created of an unchanging substance not of Earth, and that the heavens contained uniform circular motion. He published his model towards the end of his life due to fear of ridicule and disfavor amongst his colleagues and church, according to most scholars. The Roman Catholic Church considered the idea of Heliocentric Theory to be heretical. Galileo would spend the last eight years of his life under house arrest for adopting this theory.

To this day it is still called the Heliocentric Theory. It is the scientific theory that explains our relationship to the Sun. It’s the reason we can predict exactly when and where planets and stars will be in our night sky views. Our first flights into space have proven its validity beyond any doubt. It has greatly shaped our understanding of our placement in the solar system. It is the foundation for some of the greatest scientific theories that have been discovered in the last 500 years.



This is a theory that encompasses of two of Einstein’s theories: General and Special Relativity. This is not an easy subject to explain.

Special Relativity deals with the structure of space-time. It states that:

1. The laws of physics are the same for all observers in uniform motion relative to one another.

2. The speed of light in a vacuum is the same for all observers, regardless of their relative motion or of the motion of the source of light.

It deals with ideas such as Relativity of Simultaneity, Time Dilation, Length Contraction, Mass-energy Equivalence, and Maximum Speed is Infinite. I’m not going to touch on any of that, but I encourage you to go and discover more on the subject.

General Relativity deals with the theory of gravitation. The best way to think about what this theory illustrates is to imagine a mattress where you have one large bowling ball representing the sun. It will sink the mattress down. Now place a baseball about 12 inches away from the bowling ball and accelerate it to the point where it circles the big bowling ball without falling in towards it or speeding off away from it. This is the model for how gravitation really works in the universe. Some of the consequences (in relation to our universe) of this idea are that:

1. Clocks run more slowly the deeper the well in the mattress they sit. So a clock sitting 3 inches from the bowling ball will run much slower than a clock sitting 20 inches away.

2. Orbits precess and change based on the axis tilt of a planet.

3. Rays of light will bend when in the presence of a strong gravitational field.

4. The universe is expanding.


All this said, and again it’s a lot to take in, is proven constantly. Since 1905 (Special Relativity) and 1916 (General Relativity), no alternative theory has been able to disprove these concepts and ideas. For example, those of you who think about time travel may be shocked to know that it’s already been done. Sorry Back To The Future II fans. NASA has proved the concept of General Relativity related to clocks and their speeds. Every clock that is sent up and orbits the Earth at a lesser gravitational pull will tick faster. It has been shown true over and over though only percentages of a second faster, but using that information we can estimate how it may work when compared to larger planetary masses and gravitational pulls. Technically time moves faster for a person on the fourth floor of a building than that of a person on the first floor, however at that short distance its completely undetectable without massive spans of time (See illustration above).  And without scientist accounting for this weird time difference your car’s GPS system will send you straight off a cliff or into a wall. That’s the Theory of Relativity occurring in your everyday life.

Light has also been shown in Hubble photographs to bend around strong gravitational pulls (see above image). This is one way we can discover black holes, which were once thought (even by Einstein) to not have the ability to naturally occur, though that has since been proven wrong by scientist gazing at our Milky Way center. (I will touch on black holes one day in much greater detail)


Moving away now from some of these widely accepted scientific theories based entirely on collections of related, observable fact, why do I bother to touch on this today? Well, really it comes down to the idea that everything we physically know and experience in our life on Earth comes from observation. The word theory is thrown around in the media, on the Internet, and in everyday life as to why something isn’t true or is conjecture or speculation in regards to our physical surroundings within the realm of science. And in the everyday life of someone who doesn’t understand or intensely study (or even bother to skim) advanced mathematics, astrophysics, cosmology, history, chemistry, biology, geology, paleontology, anthropology, botany, or any other field that attempts to understand our physical environment; it’s easy for that same person to confuse the context of the word theory in a scientific field. When we see a scientifically published article that passes reproducible testing and overwhelming observable evidence (that also means it isn’t likely to be changed by insertion of any new evidence) on a subject we aren’t familiar with and say things such as, “It’s just a theory,” we are actually out of context in regards to science.

In regards to my original gasoline price example the word theory is in its proper context, because I am speculating or making assumptions on unknown information to me. For you to say, “It’s just a theory,” would be completely correct. But the Heliocentric Theory and the Theory of Relativity aren’t assumptions or speculation based on unknown information. These are (as to this day) still reproducibly provable and are even useful and accurate on all predictions made using them as the starting point. The amazing thing is that people like Einstein, Newton, Copernicus, Hawking, and others were predicting future concepts  long before testing could come and prove them and they would have labeled them hypothesis’s. They don’t publish works that lead to massive speculation and overwhelming doubt. They require intense research, observation, testing, re-testing and peer review. Even crazier is that nothing has proved Einstein’s Theory of Relativity wrong yet (Though scientists at the CERN facility thought they may have last year, but then realized it was due to equipment failure). However, even if something ever does prove Einstein wrong, the scientific community would gladly accept it as a welcoming of new knowledge and new rigorous testing and would continue forward. Knowledge of our human experience isn’t ultimate and is ever evolving, but a speculative theory in everyday terms is nowhere near the same thing as a published, peer reviewed scientific theory in scientific terms. A person calling an accepted scientific theory, “just a theory,” is interesting in that it does show a trait in them relating to the beginning thoughts of being deductive in nature, which is highly necessary in the scientific method, but the trait that lacks is follow-through which requires massive amounts of evidence and testing to disprove a current theory. I know that if I drop an apple it will fall to the ground (Thanks Isaac!), but I also know that if I drop an apple on the moon it will fall slower due to the moons smaller mass (Thanks Albert). I sure as hell am going to have a hard time proving their theories wrong.

Want to learn more about the Theory of Relativity? Check out the following book, which helps to explain it for laymen like most of us…



Or feel free to comb through a list of Einstein’s actual published works here.