In Chapter 1, we argued that technical artefacts such as aeroplanes, electric drills, computers and ballpoint pens differ from both physical objects and social objects in that they embrace something of both. Technical artefacts are tangible objects with physical properties, but they are also objects with a function, which they have in virtue of their embeddedness in use plans aimed at the achievement of human purposes. In Chapter 2, we examined the way in which technical artefacts come into being, by way of a design process, and in Chapter 4, we considered the knowledge that this requires. In this chapter, we show that to view technology as merely a ‘collection’ of technical artefacts would be an immense oversimplification. In so doing, we would completely fail to acknowledge the layeredness that is such an important feature of modern technology: the technical artefacts discussed so far are building blocks in wholes of a far greater complexity. Although one cannot build ‘loose’ technical artefacts that are as big as the earth itself- where would one be able to assemble them? - the wholes or systems central to the present chapter do, in fact, span the entire globe. We shall see that as a result of the character of these sorts of systems, the principles traditionally adhered to by engineers when designing technical artefacts, and the kind of knowledge upon which they rely in the process, cannot remain unaltered when it comes to the matter of the designing and implementing such complex things. As has already been noted in Chapter 3, this also has consequences for the ethical dimension of technology.