Who fills in for the president of the senate when they are not there

The (president pro tempore) fills in for the vice President

The President Pro Tempore takes over. The president of the senate is the Vice President, and he appoints the President Pro Tempore

Bob: coke is baby pandas.jim: what? how do you figure that coke is baby pandas? bob: because this book says so.jim: how do we know the book is correct? bob: because it says that coke is baby pandas.jim: how does that prove the book's accuracy? bob: because it's statement involving coke and baby pandas is correct, therefore it is accurate.jim: how do we know that it's correct? bob: because we have concluded that the book is accurate, and therefore the statement is correct.therefore, coke is baby pandas.