Observation, Hypothesis, and Theory

A friend asked me to explain hypothesis and theory. There are so many excellent resources on this topic, I should simply point the reader toward such. For example my favorite is "The Ring of Truth" by  Dr. Philip Morrison and Phylis Morrison, both of whom have passed from this life, leaving an excellent legacy of science and science writing behind them. 

Still it is always educational for a writer to write upon a given topic. No better way to learn (or relearn) than to teach. So here is my expression.  

I. Definitions

Observation: A statement about things you can see, hear, taste, feel, and so forth. Example: Fossils exist because we actually can dig such up and hold the fossils in our hands. 

Observations are often combined. Fossils are old and can be chronologically ordered, because we believe in related geological processes, which were independently observed and determined. 

We have natural observations, which are those made by simply looking at the things around us, within arm's reach or within the World or the greater Universe, with our naked senses, or enhanced by instruments such as microscopes, telescopes, spectrometers, and so forth. We also have have controlled observations, e.g. experiments, where we poke something to see what will happen. For example, poking a bear generally leads to a really scary adventure.

Hypothesis: A collection of statements, yet to be proven true, usually formed by inference from observations or by synthesis from one or more theories and observations. 

Conjecture: A guess. I had thought of a conjecture as being a hypothesis dependent on another hypothesis, but the Oxford Dictionary assures me that conjectures are just guesses, without any supporting inferences from observations. 

Theory: A collection of statements, accepted to be true via discovery of positive proofs, and by the absence of negative proofs.  A hypothesis is promoted to being a theory by means of positive proofs. Similarly, a hypothesis can be discarded by means of negative proofs. Proofs can be based on observational tests or upon theoretical analysis, or both. 

Note: theories are proven by inference, by "looking and seeing". Theorems are deduced from broader theories. Example: I hold to the theory that all life evolved from earlier different forms of life, in incremental mutations one generation to the next. From this theory plus knowledge of rates of biological mutation and knowledge of the current diversity of life, I can put forth the theorem that life has been around for a long time.

Test: A statement, formed by deduction from one or more hypothesis, usually in combination one or more related theories as well. A test is typically in the form of an "if" statement: if so, this. When you want to prove a hypothesis, you must propose some tests. No tests, no proof. 

Experiment: The comparison of tests with corresponding observations.

Negative proof: The case when tests and observations do not agree, or the case where established theories can be analyzed to show the hypothesis can not be true.

Positive proof: The case when tests and observations do agree. (In the case where established theories can be analyzed to show the hypothesis must be true, the result is a theorem.)

Whimsical musing: A hypothesis for which there are no possible tests, no related theories, and hence can never be promoted to being a theory.

Darn good theories (also known as "laws of nature") are those where we have looked for a long time, made a lot of tests, did a lot of experiments, did not find a negative proof, and found lots of positive proofs. Examples: The Theory of Evolution is a darn good theory. The Hypothesis of Divine Creation is a whimsical musing. 

Provisional Theory: All theories are provisional in the sense that a negative proof might one day be discovered, even when that possibility of negation becomes vanishingly small. Example: The Universe is old. It is going to stay old. But who knows, maybe it is actually young and just looks old? 

However, we do categorize some theories as being provisional in that it is convenient to accept the theory for the time, but we are aware of flaws. There might be a better theory someday. The Standard Model of high energy particle physics might be considered provisional. It works very well, but there are annoyances, incomplete parts, and a lot of it is just plain observational. It may be extended and modified or even replaced someday.

II. The Growth of Knowledge

When theory is extended to new cases, or modified for new cases, it does not necessarily invalidate the previous understanding of the theory. Example: Newton was not killed by Einstein. Finding a new earlier branch to the human family does not make evolution wrong or evolutionists liars. If a magnetic monopole ever shows up, something will be changed in the current understanding of physics, but classical physics is still valid in its realm.

With all of these definitions in mind, how does the body of knowledge grow? The growth goes something like this.

Most often, a direct observation is involved, accompanied by the emblematic question "huh?" We call this the Revelation of Reality. 

The Revelation of Reality is celebrated. You may have been taught some of the classic visual imagery, such as "Newton receives the Revelation of Reality whilst watching apples fall from a tree" or the not as well known "Faraday grazes deeply into the candle flame and finds the Universe". Not to be overlooked is "Darwin sees a finch he had not seen before", and the countless occasions of "that's not noise!" 

A hypothesis is formed to explain the Revelation of Reality. 

Every now and then civilization is in a state that tolerates Revelations of Reality. In such states, radical hypothesis might be put forth. Indeed, frequently an overwhelming number is put forth, without anyone being burned at the stake. We call such states "healthy".

Tests are proposed and implemented, results obtained and verified. 

Many who accepted the hypothesis before the test results were obtained, accept the results in favor of the hypothesis, and ignore any other. We call this "snap judgement".

Many who rejected the hypothesis before the test results were obtained, accept the results not in favor of the hypothesis, and ignore any other. We call this "knee-jerk rejection".

Fortunately, there are a few who are willing to stare into the candle flame and be neither a snapper nor knee-jerker. If one or more of these few is also capable of good communication, e.g. writing compelling essays, the hypothesis may have a chance to progress into being a theory.