# “You Cannot Discover What You Cannot Make”: Lee Cronin on Programming Chemistry

Page: https://stenobird.com/podcast/mendelspod-podcast-742570/you-cannot-discover-what-you-cannot-make-lee-cronin-on-programming-chemistry
Text version: https://stenobird.com/podcast/mendelspod-podcast-742570/you-cannot-discover-what-you-cannot-make-lee-cronin-on-programming-chemistry.md
Podcast: [Mendelspod Podcast](https://stenobird.com/podcast/mendelspod-podcast-742570)
Published: 2026-08-20T16:54:41+00:00
Episode link: https://www.mendelspod.com/p/you-cannot-discover-what-you-cannot
Audio file: https://api.substack.com/feed/podcast/211796999/11b365eba1db9dfa112923deef9d7c6b.mp3
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Duration seconds: 329

## Resource

This is a free preview of a paid episode. To hear more, visit www.mendelspod.com Those of us in biology tend to think that chemistry is rather straight forward. But today’s guest says there’s quite an art to synthesizing a molecule. A few years ago, Lee Cronin, a chemistry professor at the University of Glasgow joined Mendelspod for a sprawling conversation about the origin of life, alien biology, assembly theory, and his conviction that chemistry could become programmable. Now Cronin is back, and that last idea has become a company that now has a “chemifarm.” First let’s look at the problem. It is easy to assume that once a drug company has designed a promising molecule, the chemists more or less know how to make it. Not so. Chemistry remains surprisingly artisanal. A molecule that looks perfectly plausible on a computer may require too many steps to synthesize, depend on unstable intermediates, or require reactions that simply aren’t known. And chemists may not discover that until they’ve spent considerable time trying. This becomes an even bigger problem in the age of AI. Algorithms can propose vast numbers of new molecules, but which ones can actually be made? And if one can’t, is there another molecule nearby in chemical space that could perform the same function but be dramatically easier to synthesize? That’s the problem Chemify is trying to solve. “You cannot discover what you cannot make,” Cronin says in today’s interview. He spent 15 years developing χDL, a programming language that reduces the work of chemistry to a set of basic operations that machines can execute. Chemify’s software can then work backward from a desired molecule to determine a possible route for making it. Its robotic systems execute those instructions in the physical world, including chem…

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