My mother said 'And what good will that do?' My father said 'Don't you want to protect them?' Rosa Luxemburg came out of the airing cupboard and she stretched a hand out towards my father; then she swayed, put a hand to her eyes, and seemed about to fall over. People caught her, gathered round, helped her to a seat in the hallway. They were saying that she must rest, my mother was saying that a bed could be made up for her in the airing cupboard. The young man and the girl were now standing hand in hand in the passage. Rosa Luxemburg was shaking her head and smiling; she was holding her hands against her breasts. I wanted to say to my father — But they are really illustrating something else, aren't they, these religious pictures? My father was watching Rosa Luxemburg. Then suddenly she stood up and swept out of the apartment; she took most of the crowd with her, as if they were the tail of a kite or a comet. The
young man and the girl were left behind. My mother was standing in the hallway chewing the insides of her lips, which she did when she was angry with my father.
Helga had gone back into her bedroom and slammed the door. Magda was banging pots and pans about in the kitchen.
My father said to the girl who was with the young man in the passage 'You are at the university?'
The girl said 'Yes.'
My father said 'What is your subject?'
The girl said 'Physics.'
My father said 'Ah then we will have a lot to talk about!'
He held an arm out to the girl. The girl was blonde with a squashed face as if there were a wind blowing against it. I could not understand why my father was not paying more attention to me. I went and stood by my mother.
It is relevant to put in here (relevant I mean in the way that this comes up in memory, relevant in the way that these occurrences were roughly coincidental in fact) what I remember of the conversations I used to have with my father when we were not reading stories: these conversations having begun around the time when the group with Rosa Luxemburg came looking for a hiding-place in our apartment; their subject also being to do with what my father talked to the young man and girl about at supper.
Sometimes when I sat with my father on the sofa in his study and he had been reading to me stories or articles about science from children's magazines, I would, at the end of whatever voyage of discovery or imagination we had been on (I was, I suppose, quite a precocious little girl) ask my father about the work he was doing at the university. He told me something of his regular work of lecturing and teaching, but I do not remember much about this. Then he told me of the work that really interested him at this time, which was outside his regular curriculum, and was to do with his efforts to understand, and to put into some intelligible language, the theories that were being propounded about physics at this time by one of his colleagues at the university — a Professor Einstein. I do not think that my father knew Einstein very well, but he venerated him, and he was enough of a mathematician to be able to try to grapple with some of his theories. I, of course, could have comprehended little of the substance of what my father said: but because of his enthusiasm it was if, on some level, I was caught up in his efforts. I had a picture of Professor Einstein as some sort of
magician: there was a photograph of him on the chimney-piece of my father's study which was a counter-balance to my mother's photograph of Karl Marx on the chimney-piece of the dining-room. Professor Einstein's head, set rather loosely on his shoulders, seemed to have a life of its own; Karl Marx's head seemed to have been jammed down on to his shoulders with a hammer. I would say to my father as we sat above the wonders of the world in our airship 'What is it that is so special about the theories of Professor Einstein?'
My father said 'Shall I try to explain?'
I said 'I like hearing you talk. It doesn't matter if I don't understand.'
This was the time — the winter of 1918-19 — when Einstein had recently published his paper concerning the General Theory of Relativity (the papers concerning the Special Theory had been published some years previously), but the conjectures put forward in the General Theory had not yet been verified. Nothing in these theories had yet much caught the public imagination: people seemed not to be ready for such images as they might evoke. But my father had become obsessed with trying to make intelligible an interpretation of the General Theory: it was this, he said, that should alter people's ideas about the universe and about themselves.
My father said 'All right, I'll try to tell you. I'm not sure, anyway, just what it means to understand.'
I think my father had already tried to explain — usually more to himself in fact than to me — the Special Theory of Relativity. I remember the phrases about there being no absolute space nor absolute time: my space is my space; your time is yours; if I am travelling at a certain speed in relation to you it might as well be you who are travelling at a certain speed in relation to me; the only thing that is absolute is the speed of light. The speed of light is constant no matter if it arises from this or that travelling hither or thither: if there seem to be contradictions, these are because the measuring devices themselves get bigger or smaller and not the speed of light. I do not suppose I grasped the latter idea: but I do not think I found if difficult to see the idea of each person, each observer or group, having his or her or its own world: was not this, after all, what I had come to feel about the people in the streets, my mother's friends, her cousins in the country? I felt sometimes that I understood even about the absoluteness of the speed of light — was not this something that my father and I felt ourselves in touch with
as we looked down on all these separate worlds from the super-world of our airship?
I said 'You are going to tell me about the new thing, the General Theory.'
My father said 'Ah!'
There are two or three particular and personalised images that stick in my mind from my father's efforts to explain to me, aged nine, Einstein's General Theory of Relativity. These images arose from the conjectu.e that light itself had weight, so that it could be bent or pulled in the proximity of matter by what used to be called 'gravity': that if there is enough matter in the universe (which Einstein thought there was) then space itself would be bent or curved — and it would be just such curvature that could properly be called gravity. The particular images suggested by my father that have stuck in my mind are, firstly, of a small group of people standing back to back on a vast and lonely plain; they are looking outwards; they are trying to see something other than just their surroundings and themselves. But they can never by the nature of things see anything outside the curve of their own universe, since gravity pulls their vision back (my father drew a diagram of this) so that it comes on top of them again like falling arrows. The second image is that of a single person on this vast and lonely plain who has constructed an enormously powerful telescope; by this he hopes to be able to break at last out of the bonds of his own vision; he looks through it; he sees — what appears to be a new star! Then he realises that what he is looking at is the back of his own head — or the place where his head now is billions of years ago, or in the future, or whatever. Anyway, here he is now with the light from him or to him having gone right round the universe and himself never being able to see any further than the back of his own head. But then there was a third image that my father gave me, different in kind from the others: which is of gravity being like the effect of two people sitting side by side on an old sofa so that the springs sag and they are drawn together in the middle: and there were my father and I sitting side by side on the sofa in his study.