So far in this series I've focused on Spinoza's critique of the religious and philosophical world view of his time. But what does he propose in place of anthropomorphic, anthropocentric belief in a transcendent creator God?
Spinoza begins his Ethics by defining some basic philosophical terms: substance, attribute, and mode. In offering these definitions, he is actually attempting a radical revision of the philosophical vocabulary used by Descartes, the leading thinker of his time, to conceptualise reality. When we understand these terms properly, argues Spinoza, we have to conclude that there exists only one substance – and that this is God.
Substance is a logical category that signifies independent existence: as Spinoza puts it, "by substance I understand what is conceived through itself". By contrast, attributes and modes are properties of a substance, and are therefore logically dependent on this substance. For example, we might regard a particular body as a substance, and this body is not conceptually dependent on anything else. But the body's properties, such as its weight and its colour and its shape, are qualities that cannot be conceived to exist in isolation: they must be the weight, colour and shape of a certain body.
Descartes's world view draws on Aristotelian metaphysics and scholastic theology in conceiving individual entities as distinct substances. Human beings, for example, are finite substances, while God is a special substance which is infinite and eternal. In fact, Descartes thought that each human being was composed of two substances: a mind, which has the principal attribute of thought; and a body, which has the principal attribute of extension, or physicality. This view famously leads to the difficult question of how these different substances could interact, known as the "mind-body problem".
The philosophical terminology of substance, attribute and mode makes all this sound rather technical and abstract. But Cartesian metaphysics represents a way of thinking about the world, and also about ourselves, shared by most ordinary people. We see our world as populated by discrete objects, individual things – this person over here, that person over there; this computer on the table; that tree outside, and the squirrel climbing its trunk; and so on. These individual beings have their own characteristics, or properties: size, shape, colour, etc. They might be hot or cold, quiet or noisy, still or in motion, and such qualities can be more or less changeable. This way of conceptualising reality is reflected in the structure of language: nouns say what things are, adjectives describe how they are, and verbs indicate their actions, movements and changing states. The familiar distinction between nouns, adjectives and verbs provides an approximate guide to the philosophical concepts of substance, mode and attribute.
If, as Spinoza argues, there is only one substance – God – which is infinite, then there can be nothing outside or separate from this God. Precisely because God is a limitless, boundless totality, he must be an outsideless whole, and therefore everything else that exists must be within God. Of course, these finite beings can be distinguished from God, and also from one another – just as we can distinguish between a tree and its green colour, and between the colour green and the colour blue. But we are not dealing here with the distinction between separate substances that can be conceived to exist independently from one another.
Again, this is rather abstract. As Aristotle suggested, we cannot think without images, and I find it helpful to use the image of the sea to grasp Spinoza's metaphysics. The ocean stands for God, the sole substance, and individual beings are like waves – which are modes of the sea. Each wave has its own shape that it holds for a certain time, but the wave is not separate from the sea and cannot be conceived to exist independently of it. Of course, this is only a metaphor; unlike an infinite God, an ocean has boundaries, and moreover the image of the sea represents God only in the attribute of extension. But maybe we can also imagine the mind of God – that is to say, the infinite totality of thinking – as like the sea, and the thoughts of finite beings as like waves that arise and then pass away.
Spinoza's world view brings to the fore two features of life: dependence and connectedness. Each wave is dependent on the sea, and because it is part of the sea it is connected to every other wave. The movements of one wave will influence all the rest. Likewise, each being is dependent on God, and as a part of God it is connected to every other being. As we move about and act in the world, we affect others, and we are in turn affected by everything we come into contact with.
This basic insight gives Spinoza's philosophy its religious and ethical character. In traditional religion, dependence and connectedness are often expressed using the metaphor of the family: there is a holy father, and in some cases a holy mother; and members of the community describe themselves as brothers and sisters. This vocabulary is shared by traditions as culturally diverse as Christianity, Buddhism and Islam. For Spinoza, the familial metaphor communicates a truth that can also be conveyed philosophically – through reason rather than through an image.