Thursday, March 7, 2013


Welcome to Common currencies. This blog is dedicated to an ongoing research project of mine. The project is about the claim that there is, or must be, a ‘common currency’ for the options available to an agent.

For a rough and intuitive sense of what a 'common currency' might be, see this page: The (very) basic big idea.

Claims about common currencies arise in various broadly behavioural and cognitive sciences, including economics, behavioural economics, behavioural ecology (or ethology), cognitive neuroscience, and neuroeconomics. I call any claim that there is, or must be, a common currency a 'currency thesis'.

Currency theses arise in what I think are strikingly different ways. Sometimes they appear in connection with claims about fitness, or subjective utility. Sometimes the issues that provoke talk of a common currency have more to do with control systems in general, or brains (including human brains) more specifically.

I’m interested in mapping the various claims made about common currencies, and the arguments both for and against different currency theses. This is a fairly large and partly comparative project, drawing on sources in a collection of disciplines. It is also a somewhat quirky project, in the sense that the interesting comparative questions I detect in this area are not - at least yet - an established topic in the philosophy of (cognitive) science.

I’m going to document some parts of the project on this site as I proceed with it. The idea is to include:
  • Descriptions of the main arguments in favour of, and against, a common currency,
  • Moves intended to develop a framework for distinguishing importantly distinct claims about a common currency,
  • Descriptions and evaluations of inferences from one kind of currency to another,
  •  Notes on key sources (historical and contemporary),
  • Working drafts of some of my own papers on these questions as they take shape,
  • Half-baked ideas that seem worth trying to get written down,
  • Other stuff I think of as I go along...
I hope the site, and the topic, attracts some interest and discussion.

(The banner picture was taken about 2/3 of the way up Kilimanjaro in 2007. It has no specific relationship to the topic, I just thought it made a nice banner.)


Added paragraph with link to 'The (very) basic big idea' on 22 April 2013.


  1. Perhaps you could start by defining what the "common currency" phrase means? A quick shufti at google left me none the wiser.

    (And yes, the intersection of philosophy, cognition, human behaviour and possibly physics is very interesting to me, so I expect to follow this blog regularly :))

    Warm Regards

  2. Good question. Thanks. Part of why I can't give a quick answer is that the different fields in which one finds talk about a common currency don't mean the same thing but it. I'll document some of the variations in future postings. But the general idea is that a currency is some scale in which the values of all (or the relevant) available options are represented. So an economist might call the currency utility of some kind. And a biologist might think of it as the fitness value of the action/behaviour. I'm working on some postings that will try to introduce some of the variation and others that will discuss the main variants individually...

  3. Hello again Lelanthran. Hopefully my most recent posting will go some way towards responding to your question:

  4. I've recently posted a short piece on 'The (very) basic big idea' and added a link to this 'Welcome' page.