This talk introduces the motivating question for this semester of the Curry-Howard seminar, which is how to organise mathematical knowledge using topoi. The approach sketched out in the talk is via first-order theories, their associated classifying topoi, and adjoint pairs of functors between the classifying topoi of theories.
The lecture notes are available here: therisingsea.org/notes/ch2018-lecture1.pdf.
For the general seminar webpage see therisingsea.org/post/seminar-ch/.