I’m most unhappy if somebody flatly contradicts something I know to be true. Reality quivers at the blow, because, If the fundamental principles of my understanding are false, I’m delusional, and I would not be mad.
It’s commonly a disagreement over remembering events, though not always. I understand that a memory is a thought you are having in the present. It is not a stored item; it is a neural circuit being re-used. And brain circuits don’t fire in isolation. They are part of a whole tangled, interconnected network, a glowing haze of electricity that envelopes your brain, each part feeding off and triggering the others, to create an aggregate identity.
Past events leave their legacy in the brain in patterns of synaptic connections, but memories are recreated every time you access them. And you alter them to make sense in the light of your current understanding: they are strands in that moment’s neural web.
So, perhaps you revise an experience to make it match those of your companions, or rationalise the number of people who were there, or add in something you learned later, or you merge two similar events. Memory is fictional, subjective, unreliable. I know this.
But it is one thing to understand it theoretically; it is another to be confronted by a blunt denial of what happened. Your memories make you who you are: “I know this. I was there. I saw it”: “I, I, I”. You are the person who was there under these circumstances. If they deny this, they are dismantling your identity. They are threatening to tear it apart, letting the darkness in. Because if I’m wrong in what I remember, my life becomes a fiction.
And my interlocutor becomes forbiddingly unknowable: Who are they? How can they sustain and inhabit this alien interior world and still be a person like me? How can we empathise with and understand each other? In one rebuttal, someone I knew is lost to me.
Obviously, I can’t leave the contradiction unresolved, and it needs to be resolved in my favour. I need to hammer away at them until they adopt my version, admit I’m right. It’s an attempt to salvage our connection; it’s a matter of survival.
Anorexia makes this worse. Your thinking becomes even more rigid, but you also become far more anxious. You automatically struggle against any suggestions from other people. The wilful, unpredictability of other, autonomous minds is terribly threatening. They’re like bulls in the china shop of your delicate personal ontology. You can’t control them and so they could destroy everything.
No wonder we become dishevelled, feral little creatures pushing people away with flailing arms, shouting “No No No”. It’s an alarm call, a call to arms, a resistance.
 “Oh let me not be mad , not mad, Sweet Heaven!
Keep me in temper; I would not be mad” – King Lear, I.5, 40-1
 With my kids, it’s just defiance of my nagging, rather than a different reality, but it still rattles me. I’ll say, “Do you have to stand right in my way when I’m trying to drain the peas?!”
Danny will say, “I’m NOT standing in your way!”
I’ll say, “What?! I’m trying to get to the sink and you’re standing between me and the sink. How is that not standing in my way. It’s a statement of fact!”
Danny will stoutly maintain, “Dad, I am NOT standing in your way!”
Jo will say, “don’t engage with it.” It’ll be unclear if she’s addressing Danny or me.
 I feel the same way about anti-vaccers, conspiracy theorists, religious fundamentalists, Trump supporters and people who think they can cure cancer by changing their diet. I don’t feel this way about Conservatives, Brexiteers, Soviet/ Russian apologists or those who have a sneaking sympathy for the Cambridge spies. I don’t agree with them, but I think I get where they’re coming from, misguided though they are.