What am I, really? Are my actions good? How can I know? Some of the most fundamental questions of life cannot be answered by a physical experiment. Instead, they live inside the realm of thought experiments, being examined through rigorous arguments and logic instead. The field of philosophy is broad, and the boundaries are fuzzy. In fact, some may even argue that the question of what philosophy is, is a deep philosophical question in and of itself. Even so, one common thread connects it all: philosophy is an attempt to explain our experiences and rationalize our choices in a rational, critical, and systematic fashion.

This is different from religion or doctrine, which asserts that one view and understanding of the world is the correct one, without asking for proof. But it is also different from science, in that philosophy attempts to answer those questions that fundamentally cannot be answered through physical experiments or numeric simulations. Even so, it also shares many similarities with science: both require logic and rigorous argument to understand the world. Indeed, science and philosophy go hand in hand, both depending on each other and complementing each other's strengths.

Philosophy is commonly divided into several subdisciplines or branches: the study of reasoning (logic), the study of knowledge (epistemology), the study of the features of reality (metaphysics), and the study of morality (ethics). Many other branches exist beyond these core branches, and each of these requires an introduction of its own.

It is easy to get lost in philosophy as a deep and tangled rabbit hole. It is not a discipline that gives answers plain-and-simple. In a sense, it is the art of asking the right questions, and learning things from that. As such, for the sake of introducing you to the concepts of philosophy, we will approach the subject with small, tangible steps, and instead show how to think like a philosopher before diving into deeper questions.

Once one starts to ask the first questions, it becomes quickly apparent that many conclusions are based on presumptions that we have simply always assumed to be correct. But how do we know for sure that those assumptions are indeed correct? What if what we believe is false? Can we verify our knowledge by critically analyzing each and every assumption we have? These, and many more such questions, form the basis of epistemology, the study of knowledge.

Metaphysics

With the unstable foundations of epistemology under our feet, and the sturdy tools of logic in our hands, we can take a look at reality itself. What is the nature of this existence we live in? How can we define the things inside? What is a person, exactly? Do we have free will? Although you may already be convinced of clear and seemingly intuitive answers for each of these questions, challenge your understanding by thinking rigorously. These deceptively simple questions quickly become very complex, and our attempts to answer them give great insight into the nature of reality. This is the realm of metaphysics, a complex field aimed at answering questions about existence itself, and many things related to it.

Ontology

Cosmology

What is the fundamental nature of the universe?
Determinism and randomness: does this affect free will?
Why do we have memories of the past, but not of the future?
Why is there something, rather than nothing?

Ethics

Building on top of the previous chapters, we now proceed to perhaps the most directly applicable discipline to our daily lives: ethics, the study of morality. What is good, and what is evil? Can something be objectively good, or is morality subjective? What choices should I make in my life? As with all such themes, these simple questions have complex, often incomplete answers. Different schools of thought build upon different core principles, and although they may appear to be similarly virtuous, the moral choices made by each of the schools of thought can conflict in fascinating ways.

Introduction to Philosophy

Table of Contents

Introduction

Logic

Epistemology

Metaphysics

Ontology

Cosmology

Ethics

Political Philosophy

Philosophy of Mind

Aesthetics

Philosophy of Science

Philosophy of Religion

Appendices