Theories and Mechanisms

Sometimes it is more natural to say

The Mechanism by which unconditional cash transfers are supposed to benefit women is not really clear

rather than something like:

There is no clear and agreed Theory which leads from unconditional cash transfers to benefits for women

… after all, it is not quite the same to talk about what Theories people might have; sometimes we just want to talk about the Mechanisms without worrying about who believes what or says what.

So we introduce another Word in Capitals: Mechanism.

Theories are human products - stories we construct to say how some part of the world works (Wallis 2015).

A “Mechanism” is just whatever the corresponding Theory is about. You could also say “A Theory is the assertion of a Mechanism”.

Theories can be more or less true or accurate..10 So we can say “hmm, look how the children’s school-work is influenced by the behaviour of their peers - what an interesting Mechanism, let’s try and make an adequate Theory of this Mechanism”.

Talking about language and things

Language World
Statement Fact
Variable-label Variable
language-Variable (a set of Variable-labels) Variable (see xx)
Simple Theory Simple Mechanism
Theory Mechanism
Theory of Change Project (see xx)

Mechanisms in Realistic Evaluation

We are using the word Mechanism here in something vaguely like the broad sense in which it is used in realistic evaluation Theory (Pawson & Tilley, 1997). But there are some differences too. There is a special brief chapter on Realist Evaluation.


Wallis, Steven E. 2015. “The Science of Conceptual Systems: A Progress Report.” Foundations of Science. Springer Netherlands. doi:10.1007/s10699-015-9425-z.

  1. Philosophers will recognise this as so-called “correspondence theory of truth” with all the advantages and disadvantages xx