At first sight the concepts of causality and meaning seem quite alien to each other, at least in the context of materialist philosophies in which causal relations are thought to exist between mind-independent entities, while meanings are taken to belong exclusively to human minds and human societies. This sharp divide is not characteristic of other philosophies, idealist or empiricist. In an idealist philosophy, such as that of Kant and his followers, causality is conceived as a conceptual condition of human experience, together with other concepts such as space and time. Hence, causality and meaning can go together. In an empiricist philosophy, such as that of Hume and his followers, causality is defined as the observed constant conjunction of two events, like the collision of two billiard balls and the changes in the state of motion of the two colliding balls. Here meaning is also linked to causality via the mediating role of the observer. But for a materialist philosopher, causality is an objective relation in which one event produces another event, whether there is a human being witnessing this production or not. Hence, if meanings are conceived as something inherently conceptual or linguistic, their relation with causes becomes problematic.

In this chapter I want to argue that the disconnection between causality and meaning is only apparent. These two concepts, on the other hand, need to be re-analysed in order for their relation to become intelligible to a materialist. Let us begin by enriching the concept of causality to get rid of its ancient connotations of linearity. The formula for linear causality is ‘Same Cause, Same Effect, Always’. Different forms of nonlinear causality can be derived by challenging the different assumptions built into this formula. The word ‘same’ can be challenged in two ways because it may be interpreted as referring both to the intensity of the cause (‘same intensity of cause, same intensity of effect’) as well as to the very identity of the cause. Let us begin with the simplest departure from linear causality, the one challenging sameness of intensity. As an example, we can use Hooke's Law capturing a regularity in the way solid bodies respond to loads, such as a metal spring on which a given weight is attached.