Out of the Medieval intellectual battles between Realists and Nominalists, one of the more interesting fruits to fall was Duns Scotus’s notion of Haecceity (this-ness), which in modern philosophy is often reformulated as a person’s essence.  Possibly against a straw-man, Scotus argued that those who sought after the principle of Quiddity (what-ness) were misguided.  The truly interesting question is not how quiddity is possible, but rather how the individuation of universals is possible.  In other words, rather than look into how we know that Socrates is a man, we should examine how the concept of ‘man’ can be broken up in such a way that gives us a Socrates.

Another way of looking at this is in terms of Porphyry’s tree.  Each genus can be divided by a differentia into species.  For instance a Substance can be either be extended or not.  If it is, then it is a a Body.  A Body can be animate or not and if so it is an Animal.  An Animal, if rational, is in turn a Human Being.  But what is the differentia that produces an individual like Plato or Socrates?

For Scotus, this differentia is a person’s haecceity.   An interesting marginal note to a person’s haecceity is that we cannot have a adequate word for a person’s this-ness.  Words fail.  The only clear way to indicate haecceity is by extending one’s finger and pointing.  Saying “this guy” tells us nothing unless we accompany the words with a gesture to represent ‘this guy’s’ haecceity.

My haecceity for the week includes unexpectedly finding out that I passed a Microsoft certification exam.  I had taken Designing and Developing Enterprise Applications using Microsoft .NET Framework 3.5 (exam 565 for short) back in November and had forgotten about it until I received notice a week ago that I had actually passed it.

Then last Thursday I did an internal presentation for Magenic on the new Prism V2 framework.  This was rather fun, thanks to my colleagues Sergey Barskiy, Colin Whitlatch, Tim Price-Williams and Wells Caughey, who helped me start taking the technology apart.

On Friday I received a request to do a brief presentation for the MS Pro’s user group.  I took the short notice as license to do something a bit off beat and ended up presenting on “The Medieval Problem of Universals and Object-Oriented Programming.”  The audience was remarkably gracious about the whole thing.   For me it was a perfect evening which started with lunch at the bar of Pappadeux with Wally McClure, the host of the ASP.NET podcast, over martinis and oysters and ended with presenting on, all things considered, a slightly mad and rather dry topic — the kind I learned to love in grad school.

The 3rd of March, furthermore, marks one year since the wonderful Carole Cuthbertson formally offered me a job with Magenic Technologies.  It is without a doubt the best job I’ve ever had.

Finally, what has two thumbs and a birthday today?

This guy.

2 thoughts on “Haecceity”

  1. kvond,

    Thank you for the link. I was completely unaware of this potential thread of intellectual history: Scotus -> Spinoza -> Deleuze | Davidson. I am also very glad to now have a new philosophical site to add to my daily reads.


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