Full Idea
Since inference is inference to the best total account, all your prior beliefs are relevant and your conclusion is everything you believe at the end. So, you constantly reaffirm your beliefs in inference.
Gist of Idea
You have to reaffirm all your beliefs when you make a logical inference
Source
Gilbert Harman (Thought [1973], 12.1)
Book Reference
Harman,Gilbert: 'Thought' [Princeton 1977], p.189