An electric circuit contains an ideal battery, an open switch, a resistor of resistance \(R\), and two identical uncharged capacitors of capacitance \(C\). In Setup 1, the two capacitors are connected in series with each other and then placed in series with the resistor. In Setup 2, the two capacitors are reconnected in parallel with each other and then placed in series with the resistor. What is the ratio \(\dfrac{\tau_2}{\tau_1}\) of the capacitive time constant of Setup 2 to the capacitive time constant of Setup 1 when the switch is closed?