Comments on “Part Two: Taking reasonableness seriously”


outside all systems?

Lawrence D'Anna's picture

meta-rationality is “reflective”—it stands outside all systems

If what you mean by “systems” is something like “formal systems of thought devised by humans”, then I’ve got no objection.

But if you mean “systems” in a much broader sense, then I do object. Meta-rationality doesn’t stand outside the ecosystem. It doesn’t stand outside the central nervous system of the person doing it. Like any human activity, meta-rationality is contained in and constrained by the limits of the systems it is embedded in.

We can use a rationalist system of thought, called “biology” to study the ecosystem. And the formal methodologies used by biologists can be supervised by meta-rational reasonableness. But that is still taking place inside the brain of an animal. That animal needs to eat or it will die. Eventually it will die anyway. These are biological facts. The human is bounded and constrained by the ecosystem.

At the same time the ecosystem is bounded by the products of human thought. If a human gets the idea in his head to build a bunch of nuclear weapons and put them in rockets and gives one man the choice to launch those rockets, then well maybe it has the deterrent effect they were looking for and maybe it wipes out life on earth.

Systems of all kinds have hierarchical relationships with each other. The nest inside each other like Russian dolls. But if you pursue these relationships far enough things often get weird. Peano’s axioms (PA) is a formal system which nests inside Zermelo-Frankel set theory (ZFC). It nests in the sense that statements and objects and proofs inside PA can be translated into their equivalent in ZFC. Anything you can say or prove in PA you can do in ZFC, but not the other way around. But ZFC is also limited. For example Cohen proved ZFC can’t decide the continuum hypothesis. What axioms do you need to prove Cohen’s theorem? All you need is PA. Weird.

Every system exists in a context that bounds and constrains its operation. Often that context is consists of other systems. Other systems that supervise it, or physically contain it, or create the preconditions for its existence. But these hierarchical relationships do not fit together into some great chain of being with an uber-system at the top. Instead, because each of these hierarchical relationships can be of a different character than the others, the systems form an interconnected web.

But even calling it a web exaggerates the unity of the thing. It temps you to say “maybe the uber-system is the network”. That kind of systemization has its place. An operating system is an interconnected web of programs, which are each themselves systems of instructions. An ecosystem is an interconnected web organisms, which are all independent biological systems. Mathematical logic is an interconnected web of formal systems which can embed in, describe and prove theorems about each other.

But as well as systematization-as-network works, it can’t systematize everything. It can’t grow to encompass everything. Reality itself does not seem to be a system. Every system exists in some kind of environment and is limited by that environment. There is no one system to rule them all.

Systems in a formal sense

If what you mean by “systems” is something like “formal systems of thought devised by humans”

Yup, exactly! Elsewhere I defined “system” in the relevant sense:

by “system” I mean, roughly, a set of rules that can be printed in a book weighing less than ten kilograms, and which a person can consciously follow.

When you write:

Reality itself does not seem to be a system. Every system exists in some kind of environment and is limited by that environment. There is no one system to rule them all.

… we are in profound agreement. This is the essence of my critique of rationalism, and the motivation for meta-rationality. That doesn’t attempt to create a meta-system, but rather works with multiple systems as all inherently limited, and as unable even in combination to fully grasp reality, which will always be more complex and nebulous than we can imagine.

Reasonableness: a comprehensive account & its completeness

Nick Hay's picture

What topics would need to be treated in a comprehensive account of reasonableness but are out of scope for The Eggplant?

Also, is there a sense in which reasonableness is complete, in that any system that could be comprehensively reasonable could also (be trained to be) rational and meta-rational? One intuition for this being that developmentally we are reasonable for a long time before we’re rational, and rationality itself took historical time to be built up out of reasonableness, but in both cases we’re using the whole of our brains and embodiment the entire time. Another, that the way we humans implement rational systems is always embodied and all the other E-s (e.g. in Lakoff and Núñez’s account of the conceptual metaphors of mathematics, and empirical accounts of our use of notation systems and computing hardware)?


I think you may have answered your own questions? :)

My take (to be elaborated in Part Three) is that rationality (probably) does not depend on any special brain mechanisms, and what we actually do when we do rationality is not different in kind from reasonableness. It’s a collection of specific cultural practices, in the same way that (for example) ballroom dancing is a collection of specific cultural practices. It seems that you have the same sense of this.

So, as to the first question, the answer ultimately is “pretty much everything about human ways of being,” because pretty much everything we do is reasonable, or gets some reasonable account after the fact even if it was irrational at the time.

Re: completeness

Nick Hay's picture

I guess I did already answer my questions! :) Your answers make good sense to me, although for the first I was hoping you might have a list of out-of-scope-of-The-Eggplant features of reasonableness handy….

Out-of-scope features

Well, the two main sources for this Part of the book are 4E cognitive psychology and ethnomethodology. I guess what I meant is I can’t do a comprehensive survey of those fields. But also there’s unenumerable aspects of everyday being that no one has ever gotten around to investigating. I wouldn’t know how to start making a list!

Add new comment


This page introduces a section containing the following pages:

  • This is not cognitive science

    The Eggplant is neither cognitive nor science, although it seeks a better understanding of some phenomena cognitive science has studied.

  • The ethnomethodological flip

    A dramatic perspective shift: understanding rationality as dependent on mere reasonableness to connect it with reality.

  • Aspects of reasonableness

    A summary explanation of everyday reasonable activity, with a tabular guide and a concrete example.

  • Reasonableness is meaningful activity

    Understanding concrete, purposeful activity is a prerequisite to understanding the formal rationality that depends on it.

  • You are accountable for reasonableness

    Accountability is the key concept in understanding mere reasonableness, as contrasted with systematic rationality.

  • Reasonableness is routine

    Routine activity usually goes smoothly overall, despite frequent minor glitches, because we have methods for repairing trouble.

  • Meaningful perception

    We actively work to perceive aspects of the world as meaningful, in terms of our purposes, in context.

  • The purpose of meaning

    Peculiar features of language make sense as tools to enable collaboration, rather than to express objective truths.

  • How we refer

    We accomplish reference by any means necessary: observable, improvised work that makes it clear what we are talking about in context.

  • ⚒︎ Reasonable epistemology

    The epistemological categories—truth, belief, inference—are richer, more complex, diverse, and nebulous than rationalism supposes.

  • ⚒︎ Reasonable ontology

    Reasonableness works with nebulous, tacit, interactive, accountable, purposeful ontologies, which enable everyday routine activity.

  • Instructed activity

    Using instructions requires figuring out what they mean in the context of your activity, and relative to your purposes.

This page is in the section In the Cells of the Eggplant.

The previous page is Part One: Taking rationalism seriously. (That page introduces its own subsection.)

General explanation: Meaningness is a hypertext book. Start with an appetizer, or the table of contents. Its “metablog” includes additional essays that are not part of the book.

To hear about new content, Subscribe by email subscribe to my email newsletter, Follow Meaningness on Twitter follow me on Twitter, use the Syndicate content RSS feed, or see the list of recent pages.

Click on terms with dotted underlining to read a definition.

The book is a work in progress; pages marked ⚒︎ are under construction.