Semantics shemantics, but--from my (long ago) Mech.Eng. background, a "mechanism" implies mechanical. This point here is connected to that point there. When this rotates, that swivels, and that other thing slides. Inputs and outputs are obviously related. Cause and effect are are clearly visible.

That maybe a restricted way of thinking--maybe too restricted for a dynamic and fluid environment of a web community--but it's the source of my gut-feel interpretation of the term "mechanism".

I'll grant you that there are some mechanisms that the realtionship between cause and effect, input and output are sufficiently non-linear, or non-determanistic that the relationship may be obscured.

1. To some this may be true for a car.

   Petrol goes in here, I get to work or the shops.

2. Or maybe the jet engine.
   • JP4 goes in here.
   • It gets ignited here in this flow of compressed air.
   • The pressure rise of the ignition acts on the turbine blades, causing them to rotate.
   • The rotation of the turbine blades rotates the compressor blades.
   • The compressor blades suck in the uncompressed air, compress it and supply it to the ignition chamber.
   • The pressure from the ignition reacts to provide forward motion.
   • The forward motion acts to supply air to the compressor blades.
   • The JP4 goes in here.

   But what starts the whole cycle? What sets it in motion? A catalyst is needed. These days it's an electric motor, in days gone by it might have been explosive cartridges.

   These mechanisms do not hold mystery for me.

The catalyst for social change is dissention.