Without going into the technical and philosophical tradition of critique of adequatio in knowledge pursuit in general, let me say that this concept refers to the questioning of methodology, approach, attitude, assumption, discourse, perspective, worldview, and so on--and, how these impact the claims of knowledge we make as thinkers.
How adequate is a person's thinking (including, methodology, etc.) to take on with adequacy a particular task, and in this case my questioning revolves around the task of gaining truth(s) about Fear and Fearlessness. I'll focus on "Fearlessness" because this is what this ning, and the historical Fearlessness Movement is all about.
How does one both pursue knowledge about Fearlessness, define Fearlessness, conceptualize it (and ourselves in relationship to it both individually and collectively, and historically, culturally, politically, etc.)? This is a methodological question. A research inquiry into Fearlessness can be loose and sort of an anybody and everybody say what they want and make claims. There is a place for that free-for-all pluralism alright in any topic as long as there are not too severe of consequences regarding what claims are to be made and implications--based on context and subject matter under investigation (e.g., a problem).
My interest has always been to let people claim what they may, inquire as they may, and let's put all that information together and see if it helps us sort out Fearlessness. However, that is a very limited methodology and approach itself, which when the stakes are high, as I believe they are today with the exacerbated Fear Problem on the planet, there may have to be less encouragement of that wide pluralistic way and focus on a more systematic way of knowledge, knowing, and understanding of Fearlessness. It is just too important of a concept and phenomena, arguably, to let anyone make claims without them being challenged by more systematic expertise and careful thought.
So, I have spent decades on this epistemological issue of adequatio when it comes to Fearlessness. The PRACTICAL suggestion of my writing this blog on adequatio is for all writers on fear (who are serious) to locate themselves, their methodology, perspective, etc. in up-front ways, so that others can assess the limitations of one's claims made because of those methodological structurations and biases.
The book I have co-authored with Desh Subba (2016), Philosophy of Fearism: An East-West dialogue is one of the shorter but good summaries of a lot of my thinking on these issues. I also wanted to leave readers here with an excerpt from my new book  about to come out in 2018 in the next few months. It is an excerpt on my (imaginary) discussion with Four Arrows (aka Dr. Don Trent Jacobs) an very important Indigeneous scholar and educator who has developed his own notions of Fear and Fearlessness over 30 years:
Four Arrows: I am noting the tension in the responses as to what we should be focusing on, Love or Fear or Fearlessness. A Fearlessness philosophy is something I have not specifically ever thought about until meeting Michael some ten years ago. I would say, Indigenous philosophy is primarily at core, in motivation and inspiration, a Fearlessness philosophy, yet I know that isn’t going to fly in the academy, and certainly not amongst philosophers. Yet it is true. Unfortunately, “Most of the education about [an] Indigenous worldview that incorporates the importance of courage does not say much about fearlessness. Nonetheless, Indigenous worldview holds that courage leads to fearlessness at a magical point when the commitment to act on courage is irrevocable. It is a kind of trust in the universe that is a legacy for all of us. We face a situation in the world that demands that we re-embrace this perspective as best we can.”[i] I have already published on my critical views about Western philosophy and the Dominant worldview re: fear and courage and how there are a lot of “half-truths put forward by Aristotle and Socrates” which just about all philosophers in the West picked up and pass on, right up until this day. Greg Cajete, Jongmin Lee and I critiqued current neurophilosophy and neuropsychology for its inadequacy and how they are so biased, requiring a radical different perspective to integrate with science that the ancient knowledge of Indigenous Peoples offers about reality.[ii] So, come to think of it, I suppose that was my ecophilosopher-self challenging philosophy as a field to ‘wake up’ to its hegemony and the dangerousness of that course. The other starting place to research on a fearlessness philosophy is to notice how these same philosophers seem to have no respect for Fearlessness, at least the way Michael and I use it.
Michael (M): I wrote a technical paper on the West’s fear of Fearlessness, and/or its lack of interest in it.[iii] You know there are multiple scholars writing a history of fear but none have written a history of fearlessness. This is a “gap” that a Fearlessness philosophy will have to address and as Rafiq said so well, we have to ask if philosophy and its methodologies as we know them today, especially in the West, can adequately research Fearlessness, including a sacred perspective, at least as Four Arrows and I have been conceptualizing it.
[i] Four Arrows (aka Jacobs, D. T.) (2016a). Point of departure: Returning to a more authentic worldview for education and survival. Charlotte, NC: Information Age Publishing, pp. 60-61.
[ii] Four Arrows (in dialogue with Cajete, G. & Lee, J.) (2010g). Critical neurophilosophy and Indigenous wisdom. Rotterdam, Netherlands: Sense Publications.
[iii] See Fisher, R. M. (2015b). What is the West’s problem with fearlessness? Technical Paper No. 53. Carbondale, IL: In Search of Fearlessness Research Institute.
Fisher, R. M. (2018). Fearless engagement of Four Arrows: The true story of an Indigenous-based social transformer. New York: Peter Lang.