Pierce's cantilever bridge

Now, how is this for a great metaphor about the careful construction of argument: in reflecting on their workplace habits and actions after the fact, a writer now understands that they were "building a bridge - Pierce’s cantilever bridge - plank by plank and each of those planks was put in place instinctively/intuitively. Pierce describes the bridge as ‘A cantilever bridge of induction, held together by scientific struts and ties. Yet every plank of its advance is first laid by retroduction alone, that is to say, by the spontaneous conjectures of instinctive reason; and neither Deduction nor Induction contributes a single new concept to the structure" (Chaffers-Jones, 2006, p. 10; citing Blaikie, 1993, p. 165, who in turn cites Pierce 1934, p. 324). What Pierce called retroduction (Hartshome & Weiss, 1960) - and at times reduction, or hypothesis - we would I think today call abduction (Chaffers-Jones, 2006). Read more on abduction here.

Like Peirce, Professor Bhaskar - initiator of the critical realist approach to research (more here) - apparently also favoured retroduction as a term to define how "we delve into underlying causal powers [...] moving from 'surface' appearances to a knowledge of 'deep' structures which cannot be obtained through sense experience'" (Chaffers-Jones, 2006, p. 11; citing Johnson & Duberley, 2000, p. 155, drawing on Bhaskar, 1979). Sense experience seems to opens up such wonderful and exotic research horizons.

I was so taken by this description that I got a copy of Peirce's collected works, to read the original author's words in full:

"Finally comes the bottom [perhaps 'ultimate' might be better?] question of logical Critic[: "]What sort of validity can be attributed to the First Stage of inquiry?["] Observe that neither Deduction nor Induction contributes the smallest positive item to the final conclusion of the inquiry. They render the indefinite definite; Deduction Explicates; Induction evaluates: that is all. Over the chasm that yawns between the ultimate goal of science and such ideas of Man’s environment as, coming over him during his primeval wanderings in the forest, while yet his very notion of error was of the vaguest, he managed to communicate to some fellow, we are building a cantilever bridge of induction, held together by scientific struts and ties. Yet every plank of its advance is first laid by Retroduction alone, that is to say, by the spontaneous conjectures of instinctive reason; and neither Deduction nor Induction contributes a single new concept to the structure (Hartshome & Weiss, 1960, p. 323-4)

Wow: I find that quite powerful (though I could do without the scatter-gun approach to capitalisation). And while I don't know enough about research design to truly say that Peirce nailed it, the word pair "Induction evaluates" (Hartshome & Weiss, 1960, p. 323) seems terrifically clear and imminently brief to me; weighing what we found in our research against some standard, theory, or idea. Though Burks suggests, "induction is an inference from a sample to a whole" (1946, p. 301) which is NOT how we see induction today: inference is not intended. Then "Deduction Explicates": what we found, in answer to our hypothesis, is explained in detail (Hartshome & Weiss, 1960, p. 323). Done. Dusting our hands together. The two main research philosophies are despatched with dispatch.

But abduction: now there seems to lie a truly philosophical approach to research inquiry. We think, and we link our thought into a meticulous scaffold using scientific rationale to pin our thinking together. Burks suggests that "abduction is an inference from a body of data to an explaining hypothesis" (1946, p. 301), but I am not sure that is helpful. Abduction seems a likely fit with action research, as well as with the more normally-associated grounded theory. It appears flexible, measured, and iterative.

So I wonder why we have fallen into the binary approach of induction and deduction only?

Sam

References:

Bhaskar, R. (1979). The Possibility of Naturalism: A philosophical critique of the contemporary human sciences. The Harvester Press.

Blaikie, N. (1993). Approaches to Social Enquiry. Blackwell Publishers.

Burks, A. W. (1946). Peirce's Theory of Abduction. Philosophy of Science, 13(4), 301-306. https://www.jstor.org/stable/185210

Chaffers-Jones, R. (2006). Reflexivity and whole brain thinking: An exploration. [Doctoral Thesis, Sheffield Hallam University]. https://shura.shu.ac.uk/19436/1/10694317.pdf

Hartshome, S., & Weiss, P. (Eds.). (1960). Collected Papers of Charles Sanders Peirce (Vol. V Pragmatism and Pramaticism; Vol. VI Scientific Metaphysics, originally published 1934). The Belknap Press of Harvard University Press.

Juicy_fish. (2025). Dusting free icon. Flaticon. https://www.flaticon.com/free-icons/clap