The source is in this tweet by Tim Ferriss dated Sep 10, 2014. I've listened to the podcast referenced there (correct link) and searched the transcript of that podcast on YouTube, but couldn't find any of those six sentences.
Another "source" is this Australia Business Insider article, which points to the source of that quote being Blake Masters's Notes from Peter Thiel’s CS183: Startup 2012 class at Stanford, but couldn't find any advice to program your mind there either.
No: This is ¾ of the/a slogan of/blurb for the tabletop RPG Eclipse Phase, not a quote from Peter Thiel. Eclipse Phase describes itself as “the post-apocalyptic game of transhuman horror”. The full quote is
- Your mind is software. Program it.
- Your body is a shell. Change it.
- Death is a disease. Cure it.
- Extinction is approaching. Fight it.
You can see the quote on the page for the first edition of the game, from 2009; you can see that this goes back to the release of the book by looking back in the Wayback Machine and finding the August 26, 2008 version of their page advertising the core rulebook book back when it was not yet released.
This quote also did not previously originate with Peter Thiel. While one can’t prove a negative, the evidence points to the following sequence of events:
Here’s the evidence. Per Google, there are no references online to this quote colocated with Thiel’s name prior to January 1, 2012, besides a note on the TVTropes page for Eclipse Phase (which contains the quote) that Eclipse Phase contains a character named “Petra Thiel”. (If I include “Peter” in the search, I also get an “Ask Ubuntu” page that’s picked up a link to this question. I won’t mention Stack Exchange links in what follows; during the duration of this research, even the time-bound results have changed as Google indexes Stack Exchange pages that point to this page.)
Extending the search through January 1, 2013 explains the reference you found to Blake Masters’s CS183 notes: We find a PDF from April 3, 2012 (per Google and per the date in the PDF) of some of the notes from said Blake Masters on the class (CS183: Startup) he took from Peter Thiel at Stanford in Spring 2012. The PDF is not from Masters, however; it’s Masters’s notes collected by John Chew. The PDF starts with the full four-part Eclipse Phase quote, unsourced, between Masters’s name and a link to a page on Masters’s tumblr, which contains links to the same notes without the Eclipse Phase quote. If we look back in time, we can see that at least between April 17, 2012 and November 11, 2012, Masters’s blog used the full Eclipse Phase quote, unsourced, as part of the masthead on every page; this is potentially the source for the quote in Chew’s PDF. After November 11 2012, Masters got the domain blakemasters.com instead of blakemasters.tumblr.com, and excluded his site from the Wayback Machine; Masters’s website returns to tumblr.com in the Wayback Machine on July 12, 2021, when it looks identical to today’s version without the quote. As of now, Masters’s tumblr page links to more notes than the PDF; the PDF only links to the notes for classes 1–5, whereas the tumblr page has notes for classes 1–19. Given the April date, this is probably because the PDF was assembled before the notes were complete; however, the Wayback Machine version of the notes from April 17, 2012 only includes classes 1–4, so the timing presented here is probably not accurate down to the “day” level of granularity.
Extending the search through January 1, 2014 adds no more results, but extending it one more month, through Feburary 1, 2014, finds the first explicit connections between the Eclipse Phase quote and Peter Thiel: there are now two more results, very similar Business Insider listicles published on January 30, 2014 on Business Insider India and Business Insider Australia (the latter of which is currently broken). They both attribute the full (four-part) Eclipse Phase quote to Peter Thiel. They source it to Masters’s blog during the period where it was off Tumblr (http://blakemasters.com/peter-thiels-cs183-startup, which now redirects to the page we were looking at above), so we cannot examine the exact contents; however, as we see above, there are two plausible paths for associating the Eclipse Phase quote with the course notes, either from the blog’s masthead (if the quote was still present) or Chew’s PDF.
After this, the association of the Eclipse Phase quote with Thiel begins to spread, although still with all four parts and mostly not as something directly attributed to Thiel. Extending the search four more months, through June 1, 2014, finds the archive of a blog by Hervé Lebret which refers to the full Eclipse Phase quote as “the sentence which comes at the top of each series of class notes”, not as something by Thiel in particular. Extending the search four more months, through October 1, 2014, finds a September 23, 2014 blog post by Joshua Berk that attributes the Eclipse Phase quote to Peter Thiel in the blog’s sidebar; it’s not clear when this quote was added, as the page is not in the Wayback Machine. Extending through November 1, 2014, we get a reference which cites the quote correctly: a blog post from October 4, 2014, by L.M. Sacasas cites the Eclipse Phase quote as “that tag line on Masters’ website”.
Running the search for 2015 gives three results: an image incorrectly attributing the full Eclipse Phase quote to Peter Thiel; and two versions, the official web page and an unofficial PDF, of a Harper’s article entitled “Come With Us If You Want to Live: Among the apocalyptic libertarians of Silicon Valley”, by Sam Frank, which describes the Eclipse Phase quote as Masters’s “motto” which comes from “a science-fiction role-playing game”, and mentions it after talking about Masters’s Tumblr.
From 2016 on, we mostly see random references to the quote that are incorrectly attributed to Peter Thiel, typically in lists of quotes or as one-off comments, with a few exceptions (not to mention the many Stack Exchange pages that mention this question): Blake Masters’s “Talent Bureau” page features the abbreviated quote in some sort of “tagline”-like position, and does not attribute it; a Reddit comment by /u/gynoidgearhead cites the full quote as “Eclipse Phase tag line (later cribbed by Peter Thiel)”; and of course, this question itself, which by now has gone into some detail on why the Eclipse Phase quote is just that, and not due to Peter Thiel :-)
Some extra context about Eclipse Phase, to help see why the quote might have become connected to Peter Thiel: Eclipse Phase describes itself, as mentioned above, as “the post-apocalyptic game of transhuman horror”, and involves player characters with separate stats for their mind and body (“ego” and “morph”), hence the first two points; they are part of a conspiracy to protect humanity, hence the fourth point. The third point is thematically linked, as mind uploading allows for cheating death and genetic engineering is omnipresent in the setting. As the first three points are broadly transhumanist, and Peter Thiel is (per Wikipedia’s categorization scheme) at least something of a transhumanist, this could be the reason for people’s enduring belief in the spurious connection.
There is precedent for the first three lines that predate the game, Eclipse Phase mentioned in Antal Spector-Zabusky's answer. A clever game designer put them together to fit their game concept.
Found this book chapter from 1994: 'The Mind as the Software of the Brain' (An Invitation to Cognitive Science, edited by D. Osherson, L. Gleitman, S. Kosslyn, E. Smith and S. Sternberg, MIT Press, 1995) written by Ned Block from NYU.
This is the title of a 1956 movie.
Clint Mansell produced a song titled The Fountain (death is a disease).
Appears to be unique to Eclipse Phase.
