I looked it up, it's this talk, which indeed is the first one about Clojure, and it's philosophical foundations:

https://github.com/matthiasn/talk-transcripts/blob/master/Hi... (slides)

http://www.infoq.com/presentations/Are-We-There-Yet-Rich-Hic... (recording)

The opening lines are:

> So I’m going to talk about time today. In particular, how we treat time in object-oriented languages generally and maybe how we fail to. So I’m trying to provoke you today to just reconsider some fundamental things that I just think we get so entrenched with what we do every day, we fail to step back and look at what exactly are we doing.

Whoever downvoted my previous comment does not know their Clojure, that's for sure.