PhilosophyWhy physics used to be one of its branches
Philosophy is the systematic study of fundamental questions about existence, knowledge, reason, mind, and values. It works through critical inquiry and pure reasoning rather than empirical experiments. Before the modern era, it encompassed nearly all fields of rational study, including physics, biology, and chemistry.
By the edgi team We find the most surprising true thing about an idea and build a 60-second lesson around it.
If you click the first non-italicized link in the main text of nearly any Wikipedia article, you will eventually arrive at the page for Philosophy. It happens because we define concepts using broader, more abstract terms. We keep zooming out until we hit the most fundamental questions, the ones Philosophy has been asking for millennia.
The Wikipedia globe logo, composed of jigsaw puzzle pieces, with some pieces missing from the top. Version 1 by Nohat (concept by Paullusmagnus); Wikimedia., CC BY-SA 3.0, via Wikimedia Commons
The mother of sciences
Philosophy is the mother of all sciences. Physics, biology, and psychology all started as natural philosophy. They only became separate disciplines once they developed their own distinct scientific methods and moved out of the house.
A painting titled "Aristotle's School" by Gustav Adolph Spangenberg from the 1880s shows Aristotle engaging with a group of his students in an outdoor setting. Gustav Spangenberg, Public domain, via Wikimedia Commons
The original method
Socrates, one of the discipline's founders, wrote nothing down. He wandered Athens, questioning experts until they realized their confidence was built on thin air. He proved that Philosophy isn't about having the right answers; it’s about asking the right questions.
Marble bust of Socrates, a classical Greek philosopher, displayed at the Louvre. Copy of Lysippos (?), Public domain, via Wikimedia Commons
The main branches of philosophy
Philosophy divides into four primary branches. Epistemology examines what knowledge is and how people acquire it. Ethics investigates moral principles and right conduct. Logic analyzes arguments to distinguish correct reasoning from bad reasoning. Metaphysics studies the fundamental nature of reality, existence, objects, and their properties.
Beyond these core areas, philosophers examine specific domains of human thought. Subfields include aesthetics, political philosophy, philosophy of language, philosophy of mind, and philosophy of religion. Academic fields also have dedicated subdisciplines, such as philosophy of biology and philosophy of physics, which scrutinize their underlying assumptions and methods.
How philosophy split from natural science
The word comes from the Ancient Greek philosophia, meaning love of wisdom. Before the modern age, philosophy described almost all rational investigation. Isaac Newton titled his groundbreaking 1687 physics book Philosophiæ Naturalis Principia Mathematica, framing his work on motion and gravity as natural philosophy.
Isaac Newton's work on gravity was written as natural philosophy before physics separated into an independent science. CC BY 4.0, via Wikimedia Commons
Over time, sciences like physics, chemistry, and psychology built distinct empirical methods and split into independent disciplines. Philosophy narrowed to focus on non-empirical questions concerning reality, knowledge, and value systems.
Philosophical methods and traditions
Philosophers rely on tools such as conceptual analysis, ordinary language analysis, critical questioning, and thought experiments. These methods test intuitions and clarify definitions without laboratory equipment.
The trolley problem is an ethical thought experiment used to analyze the moral difference between actively causing harm and allowing harm to occur. Original: McGeddon Vector: Zapyon, CC BY-SA 4.0, via Wikimedia Commons
Distinct global traditions have shaped this inquiry. Western philosophy began in Ancient Greece. Arabic-Persian philosophy focused heavily on the relationship between reason and religious revelation. Indian philosophy combined spiritual enlightenment with studies of knowledge and reality, while Chinese philosophy historically concentrated on social conduct, government, and self-cultivation.
Test yourself
Someone says honesty means always telling everything. Which reply is philosophical?
Ask if you should tell a killer where a friend hides. A counterexample tests the definition and pushes the speaker to revise it, which is the claim, objection, revision loop.
What was Socrates' main method for examining an idea?
Testing definitions with counterexamples. He asked people what words like courage meant, then raised cases that broke their definitions, so they had to revise them.
A friend says "fairness means treating everyone identically." Which reply is Socratic?
Is giving a child and an adult equal portions fair?. A Socratic reply tests a definition with a concrete case, so the speaker sees where it fails. The other options just state a view or point to a debate.
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Some historical sources suggest the pre-Socratic thinker Pythagoras coined the term, though this attribution remains uncertain. The word entered the English language around 1175 CE by way of Old French and Latin.
What questions did Immanuel Kant use to define philosophy?
Immanuel Kant proposed that the overall task of philosophy unites under four basic questions: 'What can I know?', 'What should I do?', 'What may I hope?', and 'What is man?'.
How does philosophy connect to modern professions?
Philosophy directly informs fields like law, business, and journalism by providing an interdisciplinary perspective. It helps practitioners examine underlying assumptions and resolve ethical dilemmas within their work.