To reason through something logically, to calculate or reckon up the implications of a situation. In Luke 20:5, when religious leaders are asked about John's baptism—whether from heaven or from men—they 'reasoned among themselves,' calculating the political consequences of each answer. The word emphasizes deliberative thinking, weighing options and drawing conclusions. It's intellectual reckoning, though in this case their reasoning is cynical: they're not seeking truth but avoiding a trap.