I hope this question isn't too simplistic but I've been in a discussion with someone who claims that no energy is transferred between a cool object and a warm one (either by radiation or conduction) because the 2nd Law of Thermodynamics states that heat always flows from hot to cold.
My intuitive understanding is that energy actually flows in both directions, but the net flow conforms to the 2nd Law as more goes from hot to cold than vice-versa. In effect, the 2nd Law is an emergent property of many interactions. Is this the case?
EDIT: I should add that I've researched as much as possible, but no sources seem to explicitly state anything but the standard 2nd Law statement. If the answer is can be found in a resource I can be pointed towards, I'd be hugely grateful and apologise for wasting anyone's time.