Full Idea
Justification requires logical rather than causal connections. That is the point of the slogan that only a belief can justify a belief.
Gist of Idea
Only a belief can justify a belief
Source
Michael Williams (Problems of Knowledge [2001], Ch.10)
Book Reference
Williams,Michael: 'Problems of Knowledge' [OUP 2001], p.122
A Reaction
It seems better to talk of 'rational' connections, rather than 'logical' connections. It isn't 'logical' to believe that someone despises me because their lip is faintly curled.