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Hypothesis and theory are two words that are often used in the field of science and research. Although these two words have somewhat similar meanings, there is a fundamental difference between theory and hypothesis.
Look at these two sentences:
“When she started to follow a new parenting theory based on a trendy book, it caused a conflict with her mother, who kept offering differing opinions.”
“She decided to drink more water for a week to test out her hypothesis that dehydration was causing her terrible headaches.”
Above the word “theory” is used in the first sentence, whereas the second one uses the word “hypothesis”. To understand the difference, let’s first see what is a theory and what exactly is a hypothesis.
What is a Theory?
Theory is an idea or set of ideas that is intended to explain facts or events. A theory is formulated after in-depth research analysis. It is always proven scientifically with evidence. The Oxford dictionary defines theory as “supposition or a system of ideas intended to explain something, especially one based on general principles independent of the thing to be explained.”
As mentioned above, a theory is usually formulated from a hypothesis. Once a hypothesis is tested and proven, it is accepted as a theory. Copernicus’ Heliocentric theory, Darwin’s theory of evolution, quantum theory, special relativity theory, are examples of some important scientific theories.
A theory can be used to understand, explain and make predictions over a concept. However, theories can be proven to be wrong as well, depending on the proof. However, theoretical knowledge is important in understanding different concepts and situations.
What is a Hypothesis?
A hypothesis is a proposed explanation based on some evidence. According to the Oxford dictionary, hypothesis is “a supposition or proposed explanation made on the basis of limited evidence as a starting point for further investigation” and Merriam-Webster dictionary defines it as “an idea or theory that is not proven but that leads to further study or discussion.”
Hypothesis is a suggested explanation to explain some phenomenon, and is based on limited data. Theory, on the other hand, is a set of ideas that is intended to explain facts or events; they are based on concrete evidence.
However, a hypothesis is not scientifically tested or proven; it is a logical assumption based on the available evidence. A hypothesis can be accurate or inaccurate. Once the hypothesis is scientifically tested and proven, it becomes a theory.
Difference Between Theory and Hypothesis
More specific differences between these two terms include the following:

- A hypothesis is typically formed before an experiment, while a theory is typically formed after several experiments or studies have been performed.
- A hypothesis is one statement; a theory is a collection of things.
- A theory is more likely to be true than a hypothesis.
- A hypothesis is usually tentative, while a theory is typically more permanent.
- A theory is always backed by evidence, but a hypothesis doesn’t have to be.
- A hypothesis is specific to a single test or observation, while a theory is a general principle that can work in multiple instances.
Examples of Theory and Hypothesis
Einstein’s theory of relativity is a theory because it has been tested and verified innumerable times, with results consistently verifying Einstein’s conclusion. However, simply because Einstein’s conclusion has become a theory does not mean testing of this theory has stopped; all science is ongoing.
One might think that a prisoner who learns a work skill while in prison will be less likely to commit a crime when released. This is a hypothesis, an “educated guess.” The scientific method can be used to test this hypothesis, to either prove it is false or prove that it warrants further study.
Simply because a hypothesis is not found to be false does not mean it is true all or even most of the time. If it is consistently true after considerable time and research, it may be on its way to becoming a theory.
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