We always need a closed galvanic path for current to flow (from Kirchhoff’s laws)!
I have just read the sentence above in a book. I understand that current need a closed path to flow but I don't know how to make that statement from Kirchhoff’s laws. Can anyone explain the relation between Kirchhoff’s laws and closed path of current?

 

Without a closed path, there is not voltage gradient. Therefore, no flow of current.

Think about it in terms of water flowing through multiple channels of a river. Flow in each channel can be calcualted from width and depth (resistance) and change in height. However, if there is no change in height, there will be no flow so all calculations are useless - no matter how the channels interconnect and "could" allow flow.