Branches of science

Science is the organized study of our universe through observation and reasoning. To manage this vast amount of knowledge, researchers divide science into three major groups. These groups are the formal sciences, the natural sciences, and the social sciences. Formal sciences study abstract systems and rules rather than the physical world. Natural sciences focus on understanding natural phenomena through empirical evidence. Social sciences examine human behavior within social and cultural contexts. Together, these basic sciences form the foundation for applied sciences like medicine and engineering.

Formal sciences operate using an a priori methodology. This means they rely on definitions and rules instead of real-world observations. While some debate if this constitutes a true science, these methods are vital for testing scientific models. Logic is a key part of this group and studies valid rules of inference. It analyzes how one proposition leads to a conclusion based on other premises. Mathematics is another pillar, traditionally covering arithmetic, algebra, geometry, and analysis. These areas study quantity, structure, space, and change.

Other formal disciplines provide specialized tools for research. Statistics is the study of collecting, organizing, and interpreting data. A statistician uses these methods to plan surveys and experiments. Information science focuses on the analysis, storage, and protection of information. Systems theory is a transdisciplinary field that studies general principles of all systems. This includes self-regulating systems like the human body or global ecosystems. Decision theory studies how agents make choices, splitting into normative and descriptive branches. Theoretical computer science applies mathematical topics to the study of computing.

Natural science relies on empirical evidence from observation and experimentation. Scientists use peer review and repeatability to ensure their findings are valid. This group is divided into life science and physical science. Life science, or biology, studies living organisms. Physical science focuses on non-living systems. It includes branches like physics, chemistry, astronomy, and Earth science. Many physical sciences also study biological phenomena, creating overlapping fields.

Physics is one of the oldest academic disciplines. It studies matter, its motion through spacetime, energy, and force. During the 16th-century Scientific Revolution, physics emerged as a unique research program. Chemistry is another physical science that studies the composition and properties of matter. It specifically looks at how substances, atoms, and molecules change during reactions. Specialized fields like biochemistry study substances in living organisms. Physical chemistry uses concepts like thermodynamics to study chemical processes.

Earth science, or geoscience, studies the planet Earth. It is a unique case in planetary science because Earth is the only known life-bearing planet. Geology is a major part of Earth science and focuses on the solid Earth. It studies rocks and the processes that change them over time. Geology can also include studying the features of Mars or the Moon. Oceanography, or marine science, is another branch that studies the ocean. Earth scientists often use tools from physics, chemistry, and biology to understand these systems.

Modern science is highly interconnected through interdisciplinarity. This means different scientific fields often work together to solve problems. Specialized disciplines may exist in multiple categories at once. For example, biophysics and quantum chemistry combine physics with other areas. These connections allow the basic sciences to support applied sciences. Engineering and medicine rely on the deep knowledge provided by these various branches. By combining different perspectives, scientists create a complete understanding of the universe.