Whether one is justified in asserting that ‘the sun always moves’ or ‘the sun never moves’ (Goodman 1978:2) depends wholly on the context in which knowledge is sought: the architect is interested in how the sunlight moves around a building; the climate scientist in how the sun moves from one angle to another in the course of the seasons; the planetary scientist in how the sun never moves relative to the planets; the solar scientist in how the sun is constantly flaring and vibrating, and the astronomer in how our entire galaxy is flying through space at approximately 600 kilometers per second (Fairall 2002:73). In each case the specialist has limited her or his field of vision to the factors that are relevant to the question that is being asked (Goodman 1978:7–17). Knowledge, then, is constituted by what is ‘true enough’ for the task at hand (Elgin 2004), rather than by access to an absolute truth.
(From L.J. Green, “‘Indigenous knowledge’ and ‘science’: Reframing the debate on knowledge diversity”. Archaeologies 4(1), 144-163)
That’s the money quote right there. The social sciences love deconstructing things. This goes for development studies too: you’ll find books upon books on all sorts of topics: what is a state, what is agency, what is development? At some point though it’s good to remember that sometimes further deconstruction yields little in terms of practical differences, and we might as well carry on under simpler assumptions.
Some corners of the internet have become quite enamoured with Newton’s Flaming Laser Sword, devised by Australian Mathematician Mike Adler. It states that “what cannot be settled by experiment is not worth debating.” This is a little strong for me, but I think a weaker version of it can be quite useful, something along the lines of “that which makes little difference does not have to be debated.” (As enriching and important that debate may be).
Basically, if the knowledge you have is good enough for the task at hand, proceed and behave as if it were accurate.
In just about no field will we ever find complete truth. But we can come close enough, for all practical intents and purposes, to proceed as if. Deconstructivism and postmodernism are excellent tools for challenging calcified bodies of knowledge; they keep us honest and force us to continuously examine our work for bias and lazy thinking. But constant deconstructing can be paralysing, and in those moments it’s worth remembering that Newton’s flaming laser sword can cut through the thicket to make a path forward.