On Telling the Truth by Harold Nicolson from Small Talk

[Anon Oby]

One is generally aware, also, when one has thrust aside an inconvenient thought and slid into its place another thought which is convenient.

This sentence is from the article mentioned in the title, and what confuses me is the italicized in the quoted-- what does 'its place' refer to? And into which did this guy slide, 'its place' or another convenient thought?

[Josef Essberger]

One is generally aware, also, when one has thrust aside an inconvenient thought and replaced it with another more convenient thought.