Science: The Systematic Pursuit of Knowledge and Truth

Science is much more than a collection of facts; it is a systematic discipline designed to build and organize knowledge through testable explanations about both the natural world and human society. At its core, science is driven by the scientific method—an empirical cycle that involves making careful observations, formulating hypotheses, testing those ideas with evidence, and drawing rigorous conclusions.

This continuous process allows the scientific community to challenge, validate, and organize a growing body of knowledge, ensuring that our understanding of the universe remains accurate and evolving.

6 steps of the scientific method in a loop — A diagram variant of scientific method represented as an ongoing process

Key Facts

Clay tablet with markings, three columns for numbers and one for ordinals — The Plimpton 322 tablet by the Babylonians records Pythagorean triples, written c. 1800 BCE

Science relies on the scientific method to produce testable explanations.
The discipline is broadly divided into natural sciences and social sciences.
Formal sciences, such as logic and mathematics, use deductive reasoning rather than empirical testing.
The roots of modern science can be traced back to the Bronze Age in Egypt and Mesopotamia.
Applied sciences, including medicine and engineering, use scientific knowledge for practical applications.

The Major Branches of Science

Picture of a peacock on very old paper — The first page of Vienna Dioscurides depicts a peacock, made in the 6th century.

To better understand the vast scope of scientific inquiry, researchers typically categorize the field into several distinct branches based on their subject matter and methodology.

Natural and Social Sciences

The natural sciences focus on studying the physical world, ranging from the smallest subatomic particles to the vastness of outer space. In contrast, the social sciences examine individuals and the complex structures of societies.

Formal and Applied Sciences

While often grouped with other disciplines, the formal sciences—which include logic, mathematics, and theoretical computer science—are unique. Instead of relying primarily on the scientific method, they utilize deductive reasoning to establish truths. Meanwhile, applied sciences take the theoretical knowledge gained from basic research and use it for practical purposes, such as in the fields of medicine and engineering.

Overview of Scientific Branches
Branch Type	Primary Focus	Core Methodology
Natural Sciences	The physical world	Empirical observation and testing
Social Sciences	Individuals and societies	Empirical observation and testing
Formal Sciences	Logic and mathematics	Deductive reasoning
Applied Sciences	Practical applications	Utilization of scientific knowledge

A Brief History of Scientific Thought

Title page of the 1687 first edition of Philosophiæ Naturalis Principia Mathematica by Isaac Newton

The history of science spans much of the recorded human experience. Its earliest identifiable predecessors emerged during the Bronze Age (c. 3000–1200 BCE) in Mesopotamia and Egypt, where early advancements in astronomy, mathematics, and medicine began to take shape.

Megaliths from Nabta Playa, constructed by Neolithic populations to coordinate astronomical observations located in Aswan, Upper Egypt.[31]

Classical Antiquity and the Middle Ages

The foundations laid in the Bronze Age heavily influenced the Greek natural philosophy of classical antiquity. During this era, scholars made formal attempts to explain physical events through natural causes rather than supernatural ones. This tradition was later expanded during the Golden Age of India and the Islamic Golden Age, which saw significant advancements, including the introduction of the Hindu–Arabic numeral system.

Framed mosaic of philosophers gathering around and conversing — Plato's Academy mosaic, made between 100 BCE and 79 CE, shows many Greek philosophers and scholars.

The Evolution of Modern Science

From the Renaissance through the Scientific Revolution and the Age of Enlightenment, science underwent profound transformations. These eras moved humanity toward a more rigorous, evidence-based understanding of the cosmos and the natural world, setting the stage for the rapid technological and theoretical expansions of the 19th and 20th centuries.

Map of Europe with dots marking cities where printing presses were established by the end of the fifteenth century — The spread of printing between 1440 and 1500.

Frequently Asked Questions

Sketch of a map with captions — The first diagram of an evolutionary tree made by Charles Darwin in 1837

Graph showing lower ozone concentration at the South Pole — A computer graph of the ozone hole made in 1987 using data from a space telescope

Two curve crossing over at a point, forming a X shape — Supply and demand curve in economics, crossing over at the optimal equilibrium

Decorated "NATURE" as title, with scientific text below — Cover of the first issue of Nature, 4 November 1869

Depiction of epicycles, where a planet orbit is going around in a bigger orbit — For Kuhn, the addition of epicycles in Ptolemaic astronomy was "normal science" within a paradigm, whereas the Copernican Revolution was a paradigm shift.

Portrait of a middle-aged woman — Marie Curie was the first person to be awarded two Nobel Prizes: Physics in 1903 and Chemistry in 1911.[133]

Scientists at the 200th anniversary of the Prussian Academy of Sciences, 1900

see caption — Budget of NASA as percentage of United States federal budget, peaking at 4.4% in 1966 and slowly declining since

Dinosaur exhibit at the Houston Museum of Natural Science

Result in bar graph of two questions ("Is global warming occurring?" and "Are oil/gas companies responsible?"), showing large discrepancies between American Democrats and Republicans — Public opinion on global warming in the United States by political party[259]

What is the difference between natural and social sciences?

Natural sciences study the physical world and its phenomena, while social sciences focus on the study of human behavior, individuals, and social structures.

How does the scientific method work?

The scientific method is an empirical cycle that involves making observations, creating a hypothesis (a testable explanation), testing that hypothesis with evidence, and drawing conclusions based on the results.

Why is mathematics considered a formal science?

Mathematics is categorized as a formal science because it relies primarily on deductive reasoning—deriving conclusions from established premises—rather than the empirical observation and testing used in the natural sciences.

What are applied sciences?

Applied sciences are disciplines that take scientific knowledge and apply it to solve real-world problems, such as engineering or medical practices.

Is science a static body of knowledge?

No. Science is a dynamic process where the scientific community continuously challenges, validates, and reorganizes knowledge as new evidence becomes available.