But every time one decision is taken over another, the outcomes differ

[shootingstar]

... She took a step closer to Nora and clasped her hands together. 'It is time, my dear, to begin.'
'If you don't mind me asking - begin what?'
'Every life contains many millions of decisions. Some big, some small. But every time one decision is taken over another, the outcomes differ. An irreversible variation occurs, which in turn leads to further variations...'

(The Midnight Library by Matt Haig, episode The Moving Shelves)

What does ". . .one decision is taken over another" mean in this context? The correct interpretation of "be taken over another" makes trouble. Does it mean something like "replaced/superseded" - "one decision gets replaced by another one"?

 

[Annabel Lee]

What does "... one decision is taken over another" mean in this context?

You can replace "over" with "rather than"; "over" indicates a preference of one decision over another.