Primary Sources – Modern Philosophy

Three Dialogues Between Hylas and Philonous by George Berkeley

A Treatise Concerning the Principles of Human Knowledge by George Berkeley

Discourse on the Method of Rightly Conducting the Reason and Seeking for Truth in the Sciences by René Descartes

Meditations on First Philosophy by René Descartes

Democracy and Education by John Dewey

Ideas and Opinions by Albert Einstein

Essays of Ralph Waldo Emerson

The Vocation of Man by Johann Gottlieb Fichte

The Science of Knowledge by Johann Gottlieb Fichte

On Sense and Reference by Gottlob Frege

The Thought: A Logical Inquiry by Gottlob Frege

The Phenomenology of Spirit by G.W.F. Hegel

The Philosophy Of History (Introduction) by G. W. F. Hegel

Philosophy Of Mind: Part Three of the Encyclopaedia of the Philosophical Sciences by G.W.F. Hegel

Being and Time by Martin Heidegger

The Question Concerning Technology & Other Essays by Martin Heidegger

What is Metaphysics? by Martin Heidegger

Dialogues Concerning Natural Religion by David Hume

An Enquiry Concerning Human Understanding by David Hume

An Enquiry Concerning the Principles of Morals by David Hume

A Treatise of Human Nature by David Hume

Practical Philosophy of Immanuel Kant

The Critique of Pure Reason by Immanuel Kant

The Critique of Practical Reason by Immanuel Kant

The Critique of Judgement by Immanuel Kant

Introduction to the Metaphysics of Morals by Immanuel Kant

Fundamental Principles of the Metaphysics of Morals by Immanuel Kant

Prolegomena to any Future Metaphysics by Immanuel Kant

Fear and Trembling by Søren Kierkegaard

The Sickness Unto Death by Søren Kierkegaard

Philosophical Fragments by Søren Kierkegaard

Monadology by Gottfried Wilhelm Leibniz

An Essay Concerning Human Understanding by John Locke

Utilitarianism by John Stuart Mill

Principia Ethica by G.E. Moore

On the Genealogy of Morals by Friedrich Nietzsche

The Portable Nietzsche edited by Walter Kaufmann

Thus Spake Zarathustra by Friedrich Nietzsche

The Age of Reason by Thomas Paine

Pensées by Blaise Pascal

The Fixation of Belief by Charles Sanders Peirce

How to Make Our Ideas Clear by Charles Sanders Peirce

The Confessions of Jean-Jacques Rousseau

The World as Will and Representation – Vol. 1 by Arthur Schopenhauer

The World as Will and Representation – Vol. 2 by Arthur Schopenhauer

The Basis of Morality by Arthur Schopenhauer

Note: You can find 135 free philosophy e-books and free online philosophy courses at Open CultureProject Gutenberg and Internet Archive both host vast libraries of e-books for free to the public.