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Sharpen your thinking.

The free and flexible app for your private thoughts.

Get Obsidian for Windows More platforms Your thoughts are yours. Obsidian stores notes privately on your device, so you can access them quickly, even offline. No one else can read them, not even us. Your mind is unique. With thousands of plugins and themes, you can shape Obsidian to fit your way of thinking. Your knowledge should last. Obsidian uses open file formats, so you're never locked in. You own your data for the long term. Free without limits. Download now

Spark ideas.

From personal notes to journaling, knowledge bases, and project management, Obsidian gives you the tools to come up with ideas and organize them.

Links Create connections between your notes. Link anything and everything — ideas, people, places, books, and beyond. Invent your own personal Wikipedia.

In Meditations on First Philosophy the philosopher René Descartes describes a series of doubts about the nature of reality, arriving at the famous phrase:

• [[I thin]]

• I think therefore I am
• Just think about it
• Thinking, Fast and SlowBooks/
• The ThingMovies/

He argues that doubting requires thinking, and therefore, the act of thinking confirms his existence.

Graph Visualize the relationships between your notes. Find hidden patterns in your thinking through a visually engaging and interactive graph. Philosophy Books René Descartes Canvas An infinite space to research, brainstorm, diagram, and lay out your ideas. Canvas is a limitless playground for your mind. Learn more. Lecture 1

Rationalists

• Reason and innate knowledge → acquire knowledge
• Fundamental truths and principles can be known independent of experience
• A priori reasoning
• Reason and deduction

Empiricists

• Experience and sensory perception → acquire knowledge
• All knowledge is derived from experience and observation of the external world
• A posteriori reasoning

Cogito, ergo sum

In Meditations on First Philosophy the philosopher René Descartes describes a series of doubts about the nature of reality, arriving at the famous phrase:

I think therefore I am

He argues that doubting requires thinking, and therefore, the act of thinking confirms his existence.

Philosophers Plugins Build your ideal thinking space. With thousands of plugins and our open API, it's easy to tailor Obsidian to fit your personal workflow. Learn more. Community plugins Calendar by Liam Cain Calendar view of your daily notes. Kanban by Matthew Meyers Markdown-backed kanban boards. Dataview by Michael Brenan Advanced queries for the data-obsessed. Outliner by Viacheslav Slinko Work with your lists. Tasks by Martin Schenck and Clare Macrae Track tasks across your entire vault.

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Access your notes on any device, secured with end-to-end encryption. Learn more.

Fine-grained control. Decide which files and preferences you want to sync to which devices. Version history. Easily track changes between revisions, with one year of version history for every note. Collaboration. Work with your team on shared files without compromising your private data.

Publish instantly.

Turn your notes into an online wiki, knowledge base, documentation, or digital garden. Learn more.

Seamless editing. Publish your notes instantly from the Obsidian app, and make it easy for readers to explore your web of ideas. Customization. Control the look and feel of your site with themes, custom domains, password protection, and more. Optimized for performance. Obsidian Publish sites are fast, mobile-friendly, and optimized for SEO, no configuration required. Explore the Obsidian Help site, powered by Obsidian Publish.

It's your time to shine.

Get Obsidian Join us on Discord Get help, ask questions, meet other Obsidian users, and learn about their setup. Discussion forum Post feature requests, report bugs, and explore in-depth discussions about knowledge management. Developer docs Learn how to build your own Obsidian plugins and themes, using our open API and documentation.