The Rat Fest

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The Rat Fest

We're thrilled to invite you to the second annual Critical Rationalist Meet-up!

By Logan Chipkin

When and where

Date and time

June 30 · 5pm - July 2 · 3pm EDT


Old Pine Community Center (talks & workshops) / Logan's House (after-hours) 401 Lombard St Philadelphia, PA 19147

Refund Policy

Contact the organizer to request a refund.
Eventbrite's fee is nonrefundable.

About this event

  • 1 day 22 hours
  • Mobile eTicket

Join us for the second philosophy meet-up in Philadelphia for three days of workshops, talks, good food, new friends, old friends, philosophizing, and laughing.

Last time, we had a very successful event in Philadelphia. People flew from all across the world to discuss, debate, and learn about some of the deepest ideas Rats of all stripes care about (critical rationalists, rationalists, etc.).

Honorary Guest Speakers (remote):

1. Ken Stanley, author of Why Greatness Cannot Be Planned: The Myth of the Objective

2. Dorian Bandy, author of Mozart the Performer

3. (q & a) David Deutsch, author of The Fabric of Reality and The Beginning of Infinity

4. (asynchronous conversation) Naval Ravikant, co-founder of AngelList. He'll be participating in an attendee-only virtual room on his asynchronous audio chat app, Airchat. The room will open a few days before Rat Fest begins and remain so until Rat Fest ends.


1. 'General Admission & Logan's House': This ticket covers one meal a day at the venue, admission to the venue, and lodging at Logan's house. This ticket is reserved for a handful of people with whom I've privately communicated about staying at my house. Please don't purchase this ticket type before speaking with me (Logan) first.

2. 'General Admission & Airbnb': We've reserved a VRBO house (similar to AirBnB) that can accommodate 15 people. If you wish to stay at this location (details here:, please purchase this ticket type . This ticket covers one meal a day at the venue, admission to the venue, and the cost of lodging. Check-in: Friday at 4:00 PM ET, check-out: Sunday at 10:00 AM ET.

3. 'General Admission': This ticket covers one meal a day at the venue and admission to the venue.

4. 'General Admission & Airbnb - Kids Under 18' - just like the 'General Admission & Airbnb' ticket, but offered at a discount for those under 18.

5. 'General Admission - Kids Under 18' - just like the 'General Admission' ticket, but offered at a discount for those under 18.


Old Pine Community Center

401 Lombard St

Philadelphia, PA



Friday, June 30th at 5 PM ET - Sunday, July 2nd at 3 PM ET

(Anyone is welcome to come Thursday for casual socializing, but the scheduled programming begins Friday.)


workshops, conference-style talks, catered meals, a night on the town, hanging out with Twitter friends IRL


Crit rats are a sprawling bunch. We're spread around the globe, so most of us don't get the chance to hang out in person too often. This event fixes that.

Plus, while online communities serve many purposes, there's nothing quite like meeting up in person to fortify a community.

To be clear, Rats of all stripes are welcome to join! Last time, we had plenty of rationalists and Bayesians.


Anyone's welcome to join! Many of the people coming are adherents of Karl Popper's philosophy known as critical rationalism, so many of the talks and workshops will be about related subjects. If the theory of knowledge and its applications is your thing, this event is for you.

If you have any questions at all, email me at, or DM me on Twitter @chipkinlogan.



About the organizer

Organized by
Logan Chipkin