Why Cell Theory Is a Theory?


Martha Robinson

Cell Theory is one of the fundamental concepts in biology that explains the basic unit of life – the cell. Essentially, it states that all living things are composed of one or more cells, and that cells are the building blocks of life.

But why is Cell Theory called a theory? In this article, we will explore the reasons behind this classification.

What is a Theory?

Before we delve into Cell Theory, let’s first define what a theory is. In science, a theory is an explanation for a phenomenon that has been extensively tested and supported by evidence. This means that a theory isn’t just an idea or guess, but rather a well-established framework that can be used to make predictions and guide further research.

The History of Cell Theory

The concept of cells has been around since ancient times. However, it wasn’t until the 17th century when early microscopes were invented that scientists could observe and study cells in detail.

One of the first people to observe cells was Robert Hooke in 1665. He used a compound microscope to look at thin slices of cork and observed tiny boxes which he called “cells”, due to their resemblance to small rooms.

Later on, in 1838, Matthias Jakob Schleiden observed plant tissues under a microscope and concluded that all plants are composed of cells. The following year, Theodor Schwann made similar observations with animal tissues and came to the same conclusion – all animals are also composed of cells. These two scientists together formulated what we now know as Cell Theory.

Why is Cell Theory Called a Theory?

Given that Cell Theory has been well-established for over 180 years now, it may seem odd to call it just a “theory”. However, as discussed earlier, the term “theory” in science doesn’t mean something unproven or uncertain.

Instead, calling it a theory signifies that it is a well-supported explanation for the phenomenon of life. Over time, Cell Theory has been extensively tested and supported by numerous experiments and observations. It has also been expanded upon to include more detailed explanations for the functions and structures of cells.


In conclusion, Cell Theory is called a theory because it is a well-established explanation for the fundamental concept of life – the cell. It has been extensively tested and supported by evidence, making it an essential framework for further research in biology.

As we continue to explore the intricacies of cells and their functions, we can be confident that Cell Theory will continue to serve as a solid foundation for our understanding of life.