Explicit, codified, propositional knowledge

Most of the knowledge that you learnt in engineering school falls into the category known as explicit, or propositional, knowledge—also more broadly defined as ‘codified knowledge’. A proposition is a simple statement that can be verified as being either true or false. These are examples of formal propositions:

There are 242 pages in the geopolymer application field guide.

Young’s modulus, E, is the ratio of applied stress divided by the resulting strain in an elastic material.

Explicit knowledge is relatively easy to distribute. It can be written down in a language that appropriately educated people will understand, with a fair chance that their interpretation, based on their own prior knowledge, will align fairly closely with the intentions of the author. Explicit knowledge can be transmitted using symbols, such as words. In written form, as information, explicit knowledge can be transmitted without anything being lost. However, as soon as someone has to listen to or read it, and then interpret its words and symbols, some of the knowledge is inevitably lost or changed because of the variations in prior knowledge between individuals. All human language use is, in effect, translation between one person’s ideas of what words mean and another person’s ideas.

Explicit knowledge can be acquired by other people. It is not easy and is prone to errors and misunderstandings, as your own experiences at university can confirm.

Other kinds of knowledge are even more difficult to transfer.

Procedural knowledge

As you would appreciate from your studies, it is one thing to acquire explicit knowledge, but quite another thing to effectively use it. We can refer to the latter as procedural knowledge: knowledge that is needed in order to effectively make use of explicit knowledge, like a sequence of instructions. However, acquiring procedural knowledge requires one to practise the instructions until one no longer needs to refer to them.

You can study a textbook on mathematical statistics and acquire explicit knowledge that is relevant for the analysis of data resulting from experiments. Once you reach that stage of understanding, you can probably pass an exam.

However, you need experience in solving many practice problems in order to acquire the procedural knowledge that would enable you to competently apply statistical techniques to analyse your data so that you can confidently draw statistical conclusions from it.

Implicit knowledge

Implicit knowledge is knowledge that has not been made explicit (for example, by writing it down), but could be if needed. It includes things like knowing where the nearest bathroom is located. It might be written down on a plan of the building somewhere, but usually, we ask someone to show us or point the way. Most of us can remember where we need to go after the first visit, so we don’t need to write it down.

The important thing to understand is that, unlike explicit knowledge, implicit knowledge can usually only be learnt with help from other people or personal experience.

Tacit knowledge

The term ‘tacit knowledge’ was devised by Michael Polanyi, who wrote, “We can know more than we can tell.” An example is the knowledge you need to ride a bicycle or tie a bow with your shoelaces. This is knowledge that we acquire by practice—often frustrating practice—until one day, we get it right. From then on, it seems to come very naturally. Just for a moment, think of trying to describe how to ride a bike with words alone.

There are several different kinds of tacit knowledge. Riding a bike could be described as ‘psycho-motor’ knowledge or ‘sensory-motor’ knowledge. This is the knowledge that enables us to respond very quickly with movements that are appropriate for certain sensed conditions. Being able to walk without falling over is another good example of sensory-motor knowledge.

Tacit knowledge becomes embedded in our minds and bodies so deeply that we forget it even exists. We simply use it when we need it. It can only be learnt by practice and experience, often with the help of someone else. However, tacit knowledge is nearly impossible to verbally describe in a way that would be meaningful to someone trying to learn it.

Another aspect of tacit knowledge can be summarised as ‘social knowledge’, which is knowledge about how to behave and interact with other people in a given setting, according to local culture (Figure 10.1). The same person may interact in different ways in different settings—for example, at home, at work, with friends, with strangers, with authorities such as police, etc. It includes ways of talking and listening, what clothing to wear, body language, etc.

In engineering, tacit knowledge includes:

• Ability to recognise objects, materials, defects, failure symptoms from appearance, sounds, smells, material feel, vibration, stains, and patterns of dirt accumulation;

• Ability to recognise certain phenomena revealed by instruments such as oscilloscopes, thermographic imagery, and high-speed cameras—for example, electromagnetic interference that affect signals in an electronic circuit;

• Visual understanding of drawings (e.g., circuit diagrams, P&ID diagrams) and the ability to visualise a three-dimensional artefact from a two-dimensional drawing or image. Also, the ability to know what is not shown in the drawing, such as power supply connections that are customarily not shown on integrated circuit logic diagrams but are implied.

• Appreciation of intrinsic beauty or the ability to create objects that will be visually attractive or beautiful to a chosen class of spectator or user.² Aesthetic knowledge can be based on other senses—for example, sound is the most important aesthetic sense in the realm of music recording.³

• Ability to create a design that is not only visually attractive but also has appropriate proportions to make the best use of materials.⁴

Subconscious thoughts, imagination, and ideas that emerge without warning.

Mathematics is often more tacit than explicit. Engineers seldom, if ever, apply the methods taught in university courses. However, we frequently use mathematical concepts when we discuss technical issues. We instinctively know, for example, that the highest point on a curve or surface has a horizontal tangent, a concept that originates in calculus. We also make instinctive mathematical decisions when choosing a simplified model that allows us to estimate design parameters faster.⁵ All this comes from repeated practice exercises in engineering school that, at the time, seemed totally unrelated to practice. Many engineers think they never use their mathematical knowledge because they are unaware of their own tacit knowledge.

Embodied knowledge

There is another kind of knowledge built into the objects that make up our world. For example, the arrangement of a supermarket represents knowledge that has been developed over decades that makes life easier for shoppers, while also creating marketing opportunities for sellers. The arrangement of shelves, price tags, product packaging, and labelling, categorisations of products on the shelves, signs that direct you to ‘cereals’ or ‘tea and coffee’, the arrangement of checkout desks and cash registers . . . these are all manifestations of what we call embodied knowledge.⁶ This is knowledge that is embodied in our world. Take roads, for example. Look at all the details of road design, line markings, reflectors, speed humps, kerb design, drainage, signs, and traffic lights; they all embody knowledge about helping people make effective use of the roads for safe transportation.

Embodied knowledge exists outside of individual people because it is embodied in objects. Sometimes it can be distributed by distributing the artefacts or images with descriptions.

Embodied knowledge is not necessarily easily accessible in the sense that a person can inspect an artefact and acquire all of its embodied knowledge. Many aspects of embodied knowledge may only be apparent to someone who has enough background knowledge. For example, much of the embodied knowledge in roads may not be apparent to a person with little or no experience of driving. Only an experienced road design engineer is able to recognise the more subtle aspects of a road’s layout and hidden features like foundations and drains.

Contextual knowledge

Some knowledge is specific to a particular context, perhaps a particular organisation or even a specific workplace. Most people can recognise an electrical switch, even if they haven’t seen that particular kind of switch before. However, knowing what a particular switch controls is a form of contextual knowledge. For example, knowing that a switch is on the wall of an American home and seeing that the movable part is in the uppermost position tells you that it is in the ‘on’ position. In many other countries, however, it would be in the ‘off’ position. This is an example of contextual knowledge: knowledge that is specific to a particular setting.