Is Evolution a Theory or a Hypothesis and Why?


Vincent White

Evolution is a topic that has been debated for centuries. It is the process by which species change over time, adapting to their environment to survive.

However, there is still confusion about whether evolution is a theory or a hypothesis. In this article, we will explore the differences between these two terms and why evolution is considered to be a theory.

Theory vs Hypothesis

Firstly, it’s important to understand the difference between a theory and a hypothesis. A hypothesis is an idea or explanation that can be tested through experiments or observations.

It’s an educated guess about how something works or why it happens. On the other hand, a theory is an explanation that has been extensively tested and supported by multiple lines of evidence. It’s an idea that has been repeatedly confirmed and can accurately predict future outcomes.

Evolution as a Hypothesis

The idea of evolution was first proposed by Charles Darwin in the mid-19th century. At that time, it was just a hypothesis, as there wasn’t enough evidence to support it fully. Darwin observed that individuals within species have variations in their traits, and those with advantageous traits are more likely to survive and reproduce.

This concept was further supported by the discovery of fossils that showed how species had changed over time. However, there were still gaps in our understanding of how these changes occurred and why they happened.

Evolution as a Theory

Over time, scientists have conducted countless experiments and collected extensive evidence supporting the idea of evolution. The discovery of DNA provided further proof of how species are related to one another and how they have changed over time.

Today, evolution is widely accepted as a scientific fact and is regarded as one of the most well-supported theories in science. It has been tested through multiple lines of evidence including genetics, fossils, anatomy, embryology, and biogeography.

Why Evolution is Considered a Theory

There are several reasons why evolution is considered a theory. Firstly, it has been extensively tested and supported by evidence from multiple fields of science. Secondly, it can accurately predict future outcomes, such as the emergence of antibiotic-resistant bacteria or the impacts of climate change on ecosystems.

Additionally, scientists use the theory of evolution to make predictions about the past. For example, they can use evolutionary principles to predict what kinds of fossils we might find in certain geological formations or to determine how old a particular rock layer is.


In conclusion, evolution is considered to be a theory because it has been extensively tested and supported by multiple lines of evidence. It can accurately predict future outcomes and has led to many important discoveries in science. While there may still be gaps in our understanding of the mechanisms behind evolution, there is no doubt that it is one of the most well-supported theories in science today.