An idea, which excludes the existence of our body, cannot be postulated in our mind, but is opposed to it.
This is somewhat perplexing. What is it for an idea to exclude the existence of our body? Or to be opposed to it? Who is doing this postulating?
The proof only deepens the mystery: “Whatsoever can destroy our body, cannot be postulated therein, therefore neither can the idea of such a thing occur in God, in so far as he has the idea of our body.”
This is helpfully clarified with “Since the first element, that constitutes the essence of the mind, is the idea of the human body as actually existing, it follows that the first and chief striving of our mind is to affirm the existence of our body.”
1) Physical, Mental, and Representational
Working this out requires a bit of heavy metaphysics, so here goes. Consider my idea of, say, Descartes. We can distinguish two aspects of this idea. On the one hand, we can relate it to its object, a certain long-dead Frenchman.
But on the other hand, we can also consider it in itself – it is, perhaps, a fuzzy idea, an idea that involves certain images or has certain associations. At this point we are not relating something in my mind to something outside it, merely examining the contents of my mind.
It also has a third, physical, aspect. Physically considered, this idea is a certain configuration or complex of neurons, things occupying space inside my skull and possessing traits like motion, mass, or charge. Spinoza is emphatic that these are just three different ways of conceiving the exact same thing – a position that was very controversial at the time but is fairly mainstream now.
But Spinoza says stuff about these aspects that’s less mainstream. He describes the second aspect, the intrinsic-mental, as ‘the idea of’ the third, physical, aspect – the idea ‘in God’s mind’. That is, God has an omniscient, 100% accurate and detailed, representation of the entire physical universe, down to the tiniest particle – and this colossal representation is the universe itself. And our own mental lives are merely parts of this – when we think, that’s God thinking our brains.
2) Destroying the Brain
But let’s descend from the grand sweep of things and see how this applies to interpreting P10. I think that ‘an idea which excludes the existence of our body’ does so in its physical aspect, not in its representational aspect. Spinoza isn’t talking about ‘the idea of my body’ in the sense that some, but not all, of my thoughts are about my body (whereas others are about, say, Descartes, or monkeys); he’s talking about ‘the idea of my body’ which is simply my body, as a mental thing – i.e. my mind itself.
(What Spinoza thinks the boundaries of this ‘body’ are isn’t clear – I think they’re the boundaries of the brain, so I’m going to replace ‘body’ with ‘brain’ here)
So how does an idea ‘exclude’ this? Since my brain is defined by its structure, whatever disrupts this structure ‘destroys’ my brain. And this might be a part of the brain itself – some configuration of neurons which emits electrical signals in a way that scrambles, destabilises, or re-routes other neurons so as to destroy the recognisable person that is ‘me’. And this physical configuration of neurons will have a mental aspect – it will be an idea.
Such an idea is ‘opposed to my mind’: it’s incompatible with the preservation of my mind, and so either my mind will overcome or neutralise it, or the mind will dissolve, split, fragment or otherwise lose its organisation. We might suppose that the radical failure of this effort is psychosis, dissociation, or catatonia.
The strength of the mind’s tendency to defuse such threats is what Spinoza calls its ‘power’. And there’s no mystery why it has this tendency: because if it didn’t, it wouldn’t exist – for there to be minds at all, they must have some ‘power’ to maintain themselves.
But now let’s go back to the first aspect – that of ‘representation’ in the everyday sense. This mental conflict, this defence against mind-toxic ideas, doesn’t tell us what things those ideas will represent. The idea which, intrinsically, represents neural structures that will destroy my mind, could ‘represent’ any external thing in the world – and that thing would then become, for me, an object of mortal terror.
For instance, it might represent ‘that the people who loved me have grown indifferent to me’, or ‘that the Church I devoted my life to is full of child-rapists’, or ‘that whites will become an ethnic minority in their own country’.
I think the real crux of Spinoza’s approach to psychology is this: the brain has a physical structure that it maintains, and this pattern is replicated in the mind as a structure of ideas that it maintains – a structure of ideas which may represent an endless variety of external set-ups in the world, depending on personal experience and socialisation.
So to understand the most basic dynamic of someone’s mind, look for a ‘worldview’ – a set of ideas about the world that form a framework in which the person feels able to live. Then treat this worldview as a ‘homeostatic’ system, detecting and correcting violations of its parameters, just like their thermoregulation or osmoregulation systems.