From Aristotle to Descartes - A Brief History of Quality

  Mai 08, 2013

In the famous book Peopleware, Tom de Marco and Timothy Lister name “Cult of quality” as the top item in their list of the six things needed to build effective software development teams. Cult of quality seems to strike a deep chord in us as human beings. Again and again I have experienced how energizing such an attitude can be. The idea of something being better than something else comes natural to us. At the same time, we quickly become uncomfortable when "quality" gets brought up.

"Quality? Isn't that subjective? A feeling? How do you prove it?"

The Origins of Quality

Interestingly enough, we can trace the origin of the term quality back to its inception. In 45 B.C., the Roman statesman and philosopher Cicero created the Latin term qualitas in his introduction to Greek philosophy. Today, it’s a word used frequently in many languages, but to the Greeks it was a technical philosophical word. The term goes back to a linguistic innovation by Plato in his dialog Theaetetus where Socrates asks the question “What is knowledge?”

Socrates started his quest to find out what knowledge is by taking on the lurking trap of the relativists, Protagoras and Heraclitus. Both meant that the world was in constant flux and that the only thing we could know was the sensations we get through our perceptions, or as Protagoras formulated it: “Man is the measure of all things.”

We recognize this stance from today’s definition of quality in business settings: Quality is the extent to which a product or service meets and/or exceeds a customer’s expectation. Quality is relative to the need of a user and is expressed as the right combination of price and quality. High quality, per se, is not desirable. Man is the measure.

The philosophy of quality.That was not the view of Plato. The short section where Plato introduces “quality” is not that easy to interpret, but I think it is fair to say that he established the term quality as something that describes persistent characteristics of our reality that exists in and by itself, that are not reducible to something else. Whiteness, for example, exists as a characteristic in itself.

This is very much the view that Plato’s great pupil Aristotle also held. In his book on logic, Organon, he develops the concept about 10 different categories we use to describe the world when we make propositions. The most important of the categories is the substance, which in many ways is the more famous Plato “idea” embedded in reality. The substance of a chair is what makes it a chair, no matter what other categories you can express about it.

Objects also have other characteristics, for example an object can be in a place, or it can be moving. Some other aspect of objects can also be measured, for example its height, which he calls the quantitative category.

However, an object also has qualities.

“By ‘quality’ I mean that in virtue of which people are said to be such and such,” writes Plato. “The body is called white because it contains whiteness.”

Quality is a property of an object that exists per se.

Quality in the Dark Ages

The distinction between quality and quantity was very important to the medieval scholastic philosophy that dominated European thinking for 500 years, which was heavily influenced by Aristotelian thinking. The scholastic philosophy of nature was centered around the qualities, and how they defined all the physical aspects of the world. Qualities are “the cause of generation and corruption and alteration in all other bodies,” according to Thomas Aquinas.

Out in the reality of manufacturing and trade, the term quality was about to get a new meaning as the guild institution spread across medieval Europe. A guild was an association with particular rights given by authorities to handle trade or manufacturing for a particular area by taking care of training and upholding certain minimum quality criteria. Minimum? How can whiteness be expressed as a minimum? How can a quality be expressed as a quantity? In the medieval world, these were very reasonable questions.

One important aspect of minimum quality was not the quantifiable part, but the trust that the manufacturer had a deep knowledge about the domain, and that buying from a person belonging to a guild would guarantee that that person had that deep knowledge. It was very common to think of the guild training as a transferring of “mysteries” from master to apprentice, a transfer of an almost magical insight into the qualities of being.

The Evolution of Quality

Over time, defining a minimum quality level more and more took the form of defined quantitative measures a product would have to have to have an expected functionality. This very much happened alongside with the scientific revolution.

The philosopher René Descartes - known for his  phrase “I think, therefore I am” - had already taken the philosophical consequences of  such a position: “The nature of body consists not in weight hardness, colour and the like, but in extension alone.” That reality is quantifiable, and mathematics is the tool to use to understand that reality. Everything else (apart from reasoning) is reducible to that quantifiable reality. Colors, heat and pain, for instance, are all just individual perceptions that are not real in themselves.

Today this is a position called reductionism, and it has dominated Western thoughts since the days of Descartes. From this perspective, the old Hellenic term quality must be viewed as obsolete. There exists no reality of its own that is not somehow measurable and cannot therefore instead be expressed as a quantity.

I think this is very much in line with modern quality management practices. Quality has come to mean two things:

  • The objectively measurable aspects of a product, most distinctly expressed as something free of fault, a la Descartes.
  • The subjective feeling of “fit for my use” by the consumer, a la Protagoras.

But can all “qualities” really be reduced to quantities? Is the energetic drive behind a cult of quality really driven only by the quest for a product that is fault free and bought by customers?

If we go back to Descartes, we can agree that quantities is about something we can measure accurately, namely extension. But if something does not have extension, how can we use exact measurement?

Maybe there lies a position in between Plato and Descartes. I think so, and its represented by the 18th century philosopher Immanuel Kant. Kant also posed the old Platonic question: “What is knowledge?” and came to the radical conclusion that knowledge is not one, but several. Kant wrote about this in his three “critiques.”

In his Critique of Pure Reason, Kant investigates what we can know about the world of nature, or the Descartian world. He does this by demarcating the properties of such a knowledge and what it can say. Quality from this view is about measurable stuff, following standards, being robust and being free of faults.

But there are also realities that can not be spoken about with this kind of reasoning.

In Critique of Practical Reason, Kant investigates what kind of knowledge we can have about the moral world, what is good. From a quality perspective, we could speak of the usefulness of something; is it valuable in my practical life?

Finally, Kant wrote about aesthetics in his Critique of Judgment. Here, he questioned: What is beautiful? As part of being human, we have the fundamental ability to have an experience of the sublime, which is the experience underlying the judgment of what is or is not beautiful. Here we have a third dimension of quality.

Quality, from this perspective, is about correctness, usefulness and the sublimely beautiful. This multi-dimensional way of looking at knowledge and quality gives a much deeper understanding of why quality, as such, engages us so much, and why cult of quality is a forceful motivator: It includes so many aspects of being human.

Quality in Today's Markets

Maybe, and now I am speculating, quality viewed as this even has emergent properties. Emergence is, in the words of Aristotle in Metaphysics, when “the whole is more than the sum of its parts.” Quality, then, would be the new level of experience, the combination of the three Kantian aspects into one whole.

Looking from this perspective, the idea of anything a customer buys being quality would be ludicrous. If I buy something I can afford to meet my needs, it does not in itself mean that I view the thing I bought as a quality product, i.e. a combination of robustness, usefulness and beauty.

It also makes it easier both to understand and relate to quality standards developed by professionals in a field, and why they often differ from the general (or market) view. As it seems, our inert drive for mastery will, when possible, interpret quality as the maximum achievement along all three axis we have talked about above. The more we know about a particular subject, the higher our expectations to call something of high quality will be.

I think even Plato would somehow been able to align with that view.

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