Reductionism is it a threat or a promise?

Why should we suppose that any physical event, no matter how simple (say the movement of a single electron, say) must have an ideational (mind) correlate?

If one chooses to hypothesize that a specific degree of physical complexity (the electron movement) is necessary for a mental phenomenon to occur, then the threat (or promise) of reductionism looms.

Unsure of my conclusion (Help!) the minutest movement of a single electron is a physical event, and it would be inaccurate to deemit  to be 'mental' or the doings of what is termed the 'mind'