Science: The Systematic Pursuit of Knowledge and the Scientific Method

Science is a systematic discipline dedicated to building and organizing knowledge through testable explanations of the natural world and human society. Rather than relying on intuition or anecdote, science is driven by the scientific method—an empirical cycle that involves making careful observations, formulating hypotheses, testing those hypotheses with evidence, and drawing evidence-based conclusions.

This process creates a body of knowledge that is never static; the scientific community continuously challenges, validates, and reorganizes information to ensure accuracy and reliability.

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

Key Facts

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.

Core Methodology: Science relies on an empirical cycle of observation, hypothesis, testing, and conclusion.
Major Branches: Divided primarily into natural sciences (physical world) and social sciences (individuals and societies).
Formal Sciences: Logic, mathematics, and theoretical computer science use deductive reasoning rather than the empirical scientific method.
Historical Roots: Early predecessors date back to the Bronze Age in Egypt and Mesopotamia (c. 3000–1200 BCE).
Applied Science: Practical applications of scientific knowledge, such as medicine and engineering.

The 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.

Modern science is categorized based on the subject of study and the methodology used to uncover truths.

Natural and Social Sciences

The natural sciences focus on the physical world, encompassing fields like physics, chemistry, and biology. In contrast, the social sciences examine the complexities of human behavior, individuals, and the structures of societies.

Formal and Applied Sciences

The formal sciences—including mathematics, logic, and theoretical computer science—are distinct because they rely on deductive reasoning (deriving specific conclusions from general premises) rather than empirical observation. Meanwhile, applied sciences take the theoretical knowledge gained from these disciplines and use it for practical purposes, most notably in engineering and medicine.

Comparison of Scientific Branches
Branch	Focus	Primary Methodology	Examples
Natural Sciences	Physical World	Empirical/Scientific Method	Biology, Physics
Social Sciences	Society & Individuals	Empirical/Scientific Method	Sociology, Psychology
Formal Sciences	Abstract Systems	Deductive Reasoning	Mathematics, Logic
Applied Sciences	Practical Application	Implementation of Theory	Engineering, Medicine

A Journey Through Scientific History

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.

The history of science is nearly as old as the historical record itself. The earliest identifiable precursors emerged during the Bronze Age in Mesopotamia and Egypt (c. 3000–1200 BCE), where early populations made significant strides in medicine, astronomy, and mathematics.

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

These early contributions laid the groundwork for Greek natural philosophy during classical antiquity. Greek scholars sought to explain physical events through natural causes rather than supernatural ones. This intellectual tradition was further enriched during the Golden Age of India and the Islamic Golden Age, which introduced critical advancements such as the Hindu–Arabic numeral system.

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

The transition from natural philosophy to modern science accelerated during the Renaissance and the Scientific Revolution. This era saw a shift toward rigorous experimentation and the publication of foundational works, such as Isaac Newton's Philosophiæ Naturalis Principia Mathematica in 1687, which redefined our understanding of physics.

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

By the 19th and 20th centuries, science became highly specialized. Charles Darwin's 1837 evolutionary tree revolutionized biology, while the 20th century brought about breakthroughs in quantum physics, chemistry—highlighted by Marie Curie's dual Nobel Prizes—and the birth of computational science.

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

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]

The Scientific Method and its Philosophy

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

At the heart of all scientific inquiry is the scientific method. This is not a rigid checklist but a flexible process of refinement. It involves the constant interplay between theory and evidence.

Philosophically, science is often viewed through the lens of paradigms—conceptual frameworks that define how scientists view a field. A "paradigm shift" occurs when the existing framework can no longer explain observed phenomena, leading to a scientific revolution (such as the shift from Ptolemaic to Copernican astronomy).

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.

Frequently Asked Questions

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

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 the natural sciences and formal sciences?

Natural sciences study the physical world using the empirical scientific method (observation and testing), while formal sciences, such as mathematics and logic, rely on deductive reasoning and abstract systems.

How does applied science differ from basic science?

Basic science seeks to expand fundamental knowledge without a specific immediate application, whereas applied science uses that existing knowledge to develop practical solutions, such as creating new medical treatments or engineering bridges.

What is an empirical cycle?

An empirical cycle is the core of the scientific method, consisting of a repeating loop of making observations, forming a hypothesis to explain those observations, testing the hypothesis with evidence, and drawing conclusions to refine the theory.

Who were the earliest practitioners of science?

The earliest predecessors to modern science were found in the Bronze Age civilizations of Egypt and Mesopotamia, who contributed early knowledge in astronomy, mathematics, and medicine.

What is a paradigm shift in science?

A paradigm shift is a fundamental change in the basic concepts and experimental practices of a scientific discipline, occurring when the current model can no longer explain new evidence.