Philosophical questions about the external world and our knowledge of it are almost exclusively raised from the armchair. The knowledge we gain in everyday life or develop through scientific investigation is considered at the conceptual level, and its claim as genuine knowledge is assessed in abstraction from its exercise and application. This intellectually aloof manner is one reason that Anglo-American philosophy tends not to inform itself directly with scientific findings. Empirical studies of the world are apt for philosophical analysis, but few philosophers use them to inform that analysis. It is not surprising therefore that engineering has so far been uncharted territory for philosophers. But what would philosophers learn if they engaged with this practical discipline, a discipline that seeks not to understand the world but to change it?
If philosophers were to look more closely at the nature of practical knowledge about the world and practical engagement in it, many of the abstract questions and doubts that philosophers ponder become harder to entertain. It is very difficult to be a sceptic about the existence of the external world when you are working with it and changing it. It is also difficult to maintain sceptical doubts about knowledge of the world if you appreciate the way that knowledge is involved in the sophisticated interactions with the world that engineers perform.
Philosophy of science has a relatively long and established tradition, but has generally excluded engineering from its compass. Although there is no sharp distinction between engineering and science, they are often distinguished by their overarching goals. Roughly: science has the aim of providing knowledge and understanding of the world, which it does by making observations and discoveries and by constructing explanatory theories; engineering has the aim of making the world a more accommodating place, which it does by designing, constructing and maintaining artifacts, processes and systems of infrastructure. In terms of meta-aims for science and engineering, you might (contentiously) add that scientists aim for truth in the theories they develop, and (less contentiously) that engineers aim to create things that are useful and reliable.
Philosophy of science has most likely flourished because of the contentious nature of the claim that science provides true knowledge. There is a gap between scientific observations and the “reality” behind those observations which scientific method cannot bridge. Philosophers work in that gap, asking whether the explanatory theories based on observations really reflect reality. In contrast, the question of whether the products of engineering effort are useful, reliable and so on is generally answered by engineering methods and is not philosophically provocative. Something either works or not – there is no gap between “apparent” and “real” functionality to be filled by philosophical reasoning.
However, if philosophers are considering the nature of knowledge about the world they should take into account the practical products of engineering as well as the theoretical products of science. It first needs to be accepted that engineers, as well as scientists, produce knowledge. Engineering is often thought of as only applied science – engineers apply scientific theory to practical problems. But successful engineering practice can be developed in the absence of scientific theory. Engineers often point out that the steam engine was initially devised, and then perfected (most notably by James Watt), prior to the development of thermodynamics. It was only through investigating the functioning of steam engines, and creating idealised models of such engines, that Carnot developed the science of thermodynamics that explains their functioning. But in the absence of this theory should we judge that engineers worked blindly, or did they develop and apply knowledge? The answer is surely the latter. This was not theoretical knowledge, however, but practical knowledge. It was not even wholly propositional knowledge – knowledge that can be written down – but engineering know-how; knowledge that is evidenced by exercise not by recitation.
Engineering has developed an impressive body of such know-how: it is on the basis of such knowledge that we commute to work, take an elevator, check the internet or get ourselves a glass of water from the tap. This knowledge is different from theoretical scientific knowledge, but not wholly distinct from it. The two sources of knowledge blur: experimental science involves a great deal of practical know-how, and engineering science involves developing theories. It is therefore essential when theorising about human knowledge, scientific knowledge in particular, to take into account this impressive body of practical knowledge alongside scientific theory.
One philosopher who appreciates the role of engineering in science and has brought it to bear on philosophical questions is Ian Hacking. Hacking’s concern was the reality or not of so-called “theoretical entities” in science. Sub-atomic particles are treated in philosophy as (merely) theoretical entities because they are not directly observable, but are posited by scientific theory to explain the observations that are made. Hacking argues that it is only when one focuses on observability, or the lack of it, that one is tempted to class entities described by science as “theoretical” and to therefore question their reality. If one focuses on the ability to manipulate those entities then one becomes less ambivalent about their existence. Hacking discusses the example of a polarised electron gun, designed to emit polarised electrons for use in experimentation. He concludes that if one can successfully design such a device and can thereby harness the behaviour of electrons, it is pretty hard to be sceptical about their existence.
Hacking points out that it is largely engineering know-how rather than theoretical knowledge that went into the design and construction of the polarised electron gun. A more timely example of engineering’s role in experimentation is the large hadron collider being built at CERN. This might be part of one of the largest-scale scientific experiments ever run, testing our most fundamental theories, but it is also an incredibly challenging engineering project. Designed to recreate experimentally the conditions at the beginning of the universe, it is expected to reveal the Higg’s Boson – the as yet undiscovered entity necessary to the standard model of particle physics. It is hoped that the collider will reveal a great deal more – possibly even lending support to supersymmetry, the theory that for every particle there exists a heavier partner, a theory which solves some major problems in the standard model. No one is sure what will happen to accepted and postulated theory when the collider roars into life, but what is certain is that the rotating beams of protons that will collide in the facility are real, not theoretical. It will be proven that we know how to get them to do what is necessary in order to learn more about them. This shows that, even without full theoretical knowledge of fundamental particles, you can engineer a system to reveal that knowledge. Hence there is something other than theoretical knowledge of fundamental particles that one can’t be sceptical of – knowledge of their existence and of how to manipulate them.
This brings us to the philosophically significant issue of theory change. One of the philosophical arguments bridging the gap between theory and reality in science is the pessimistic induction. This is the argument that current theories should not be accepted as true on the basis that they are highly likely to turn out to be false. Past experience tells us that new theories arrive and usurp accepted scientific belief, as the Newtonian system was ousted by Einstein’s General Theory of Relativity. Therefore we should expect current theories to be similarly overturned. The conviction that current theories will end up on the scrapheap even leads to scepticism about the very idea of scientific progress. If new theories emerge that paint right over what was previously believed, offering a fundamentally different picture of reality, they do not build on previous scientific knowledge but replace it.
Joseph Pitt, in his article “What Engineers Know”, argues that the pessimistic induction allows engineers to score a triumph over science. This is because the scrapheap of engineering is unlike the scientific scrapheap. When a new engineering design is developed, say for an aircraft, it does not overwrite previous designs. However revolutionary it is in terms of materials used, how light, fuel efficient, fast or capacious it is, while it improves on existing planes, it cannot show that they fail to work. It builds on existing design and improves it, rather than showing existing designs to be flawed. To take a more revolutionary example, internet-based communications such as email do not render telephone communications obsolete. The new methods devised for routing information across networks have not rendered older means of connecting people irrelevant. Rather, a new mode of communication has developed as an additional tool that exists alongside the older technology (which continues to be improved in its own right).
Pitt goes on to argue that this shows that the practical knowledge of engineers is more secure than scientific, theoretical knowledge. But there is no need to take sides. The important thing is that applied knowledge – applied theoretical science, applied engineering science or pure engineering know-how – does not leave the same room for philosophical doubt that theoretical knowledge does. Knowledge of something like how to build an aircraft stays useful, even if more useful knowledge exists – and as mentioned earlier, usefulness is not generally philosophical contentious. If we are willing to accept that a large part of our shared knowledge of the world includes engineering knowledge, then we can conclude that a lot of our sophisticated knowledge is steadfast; that it has been, and will continue to be, developed and improved upon. This makes sense of what remains self-evident even in the light of the pessimistic induction, that we have made progress in our ability to adapt the natural world and to build artifacts that allow us to live more comfortably in it.
An important aspect of engineering knowledge in addition to its practical nature is the fact that it is most often shared knowledge – shared by researchers, design teams and even whole corporations. Complex engineering projects involve a number of people working on different aspects in different locations. Take, for example, the development of the Airbus A380, the current largest passenger plane. This project has taken advantage of engineering and manufacturing expertise across Europe. Developing, testing and constructing this aircraft was not simply a matter of copying what has been done before on a larger scale, but posed novel challenges due to the new services that Airbus planned to incorporate into the plane and to its sheer size. The fact that there were novel challenges involved was evidenced by the fact that the project has hit upon numerous delays in delivery. Lessons are learned through such challenges, however, and new knowledge is created on how to deal with the problems of constructing larger and more complex aircraft. However, this is not knowledge held by any one person or single team. It is emergent knowledge, dispersed amongst people, held in various databases, designs and so on (and even gained by competitors).
Looking at engineering knowledge in this way reveals that a great deal of important, knowledge does not reside in individuals’ heads. Realising this is relevant to addressing scepticism about knowledge in general. Kieron O’Hara in Plato and the Internet argues that the sceptical questions raised within the philosophical model of knowledge as “justified true belief” have less purchase in a world where a significant amount of knowledge is held by organisations rather than individuals, where it is held in different peoples’ heads (and laptops), in databases, in records and on the internet. Sceptical worries that are based on the possibility that one could be dreaming, or could be deluded by an evil demon, meaning that one’s beliefs or perceptions are radically wrong, do not apply to knowledge which is not in the form of a belief in an individual’s head. Hence, once more, engineering knowledge is less vulnerable to this form of sceptical doubt than other forms of knowledge.
A final kind of philosophical worry that might be allayed by looking at how we manipulate the world concerns the questions that arise about the relation between the mind and the body. Descartes, in his Meditations, famously cast doubt on the necessary connection between mind and body, imagining that he could conceive of himself as existing separately from his gross physical body, as a purely mental thing. This Cartesian dualism has led to philosophical scepticism about the existence of other minds. If we imagine minds and bodies as being somehow independent, we can imagine bodies existing without minds. Thus we can conceive of the possibility that the bodies around us are hollow automota without the mental life that we have. However, robotics itself could provide us with an interesting perspective on this issue.
One of the most valuable contributions that engineering has made to human welfare is through its collaboration with medicine. Biomedical engineering is responsible for developments in keyhole surgery and in the development of functional prosthetic limbs. To be able to design and make a limb that responds to an individual’s intentions and moves to some degree like a real limb gives a different perspective into the relation between mind and body. Modern prosthetic limbs work on the basis of understanding the working of the nervous system, and therefore work entirely on the physical level. However, the aim of such devices – and at present they are a long way from this aim – is for them to work as a normal limb, to move on the basis of thought, of mental inclination, to be a natural expression of behaviour. The design and fitting of such limbs is a matter of intervening in the process of connecting mental activity to behaviour. Being able to affect such a connection narrows the window for philosophical doubt about the intimate connection between mind and physical behaviour. It is to experience how mind and body connect, not just to have a more detailed physical theory of how the body and brain interact. As engineers get better at making such limbs work, their experience of connecting mind and body will become ever more significant.
Once one is out of the armchair, out of the laboratory even, scepticism is much harder. This is an extension of Hume’s point that in one’s everyday life it is impossible to be a sceptic due to the distractions of leisure or the pressures of merely surviving. If we look at practical knowledge of the world and see how it is generated and used, the gap between appearance and reality, where sceptical doubts arise, is narrowed. When one realises that much knowledge is know-how, the gap between theory and reality closes. If one accepts that not all knowledge is beliefs in individuals’ heads, the worry about delusion is less pressing. And if one is working in the gap between mind and body, helping people to connect mind to an extended, prosthetic body part, the possibility of mindless bodies becomes less real.
Natasha McCarthy is policy advisor at The Royal Academy of Engineering