“If it won’t work directly, can something go in between?”

Intermediary: An intermediary carrier or process is used to reach a result.


Almost all goods are packaged for shipping, as they are not durable enough to withstand the elements between manufacturing and distribution.


A carpenter’s nailset addresses the problem where a large heavy hammer needs to strike a small nail without damaging the surrounding material. It serves as an intermediary between the striking hammer and the hollow tip of the nail head.

Guitar pick

A guitar string needs to be a certain tension and thickness to function properly, but this could feel like a cheese grater to the musician playing. The guitar pick serves as an intermediary between the thin strings and fragile flesh.


Absent cutlery, getting food from the plate to the mouth could be a messy or even painful process if the food is hot enough.

An oven mitt serves a similar intermediary function, getting hot food to the table without burning the cook’s hands.

Nuclear reactors

Nuclear reactors run one coolant over the core to gather extreme heat but then use a heat exchanger to transfer this heat to a steam cycle which runs a turbine.  This keeps the nasty radioactive primary coolant isolated with the core and away from the more mundane equipment like the turbine generator and its own waste heat cooling system.

More examples

As I stumble across real world examples of this Inventive Principle in action I add them here.

Your turn

What problems do you face that this inventive principle could help solve? Have you used this principle before?