There was a caretaker on the property Berk had borrowed. He had things ready when the two men arrived. Mart determined to put everything connected with ONR out of his mind while he was there. He sat down and wrote a letter home, which helped in that direction.
In the morning he arose in the clear mountain air, and to the enormous song of birds in the pines beyond the house, and he felt that he had truly forgotten all else but this. The smell of bacon and eggs floated in from the kitchen as he met Berk outside the door.
'It's nice to know a psychologist who knows a millionaire. Could we have had breakfast in bed if we had ordered it?'
Berk laughed. 'Not on your life. Wait till Joe gets you out in the woods. Then you'll see how much coddling you'll get.'
'Let's not take him along,' said Mart. 'I'd like to be alone as much as possible.'
'Sure. Joe won't mind. He's the one who knows all the good fishing holes, though-'
'The fish don't matter,' said Mart.
The forest was moist with dew, and the pre-dawn chill remained in the ravines through which they descended towards the river. It was still shadowed by the mountains here, and quiet except for the few birds who had not abandoned its grey light for the pink-tipped hills above.
Mart knew at once that this was what he needed. He donned the hip boots and tested the spring of the new glass rod he had rented.
'I guess I'm old-fashioned,5 he said. 'I like the feel of the old ones better.'
'I'm still using mine,' said Berk. 'Matter of fact, I believe it's the same one I had the last summer we were together.'
They sloshed out into the water a little way above a quiet pool. It wasn't wide enough for both of them there, so Mart moved along upstream. 'Some guy published an article the other day,' he said, 'in which he claimed the average time of catching a fish in a stream like this is two hours and nineteen minutes. Didn't we do better than that?'
'Seems like we did a lot better. If we don't, we'll have to get Joe to make a lunch today.'
They did considerably better. By noon, Mart had six and Berk had seven good trout.
'I'll write the fish researcher a letter,' said Mart, 'and your family will eat trout for a week.'
After lunch they sat with their backs against a tree on the bank and watched the water flowing past.
'Have you got any attack on the project at all?' said Berk.
Mart told him about the last seminar. 'Dykstra may be entirely right. His maths makes a pretty picture. But I was serious when I suggested the re-examination of the postulate of equivalence — at least as it now stands.'
'You're ahead of me,' said Berk. 'What is the postulate of equivalence?'
'It was proposed by Einstein in one of his first papers, the 1907 one, I think. He postulated that the effects of inertia are equivalent to those of gravity.
'That is, in an object propelled at a constant rate of acceleration, a man would feel effects that could not be distinguished from those of gravity. He could walk, function, and would have weight just as if he were on a large mass having gravitational attraction.
'Conversely, an observer inside a freely falling elevator in Earth's gravitational field would observe no effects of gravity inside that elevator. He could stand on a scale, and would register no weight. Liquid would not pour from a glass. It has been stated that no mechanical experiment could ever reveal the presence of Earth's gravitational field in the interior of any such frame of reference moving freely in this field of gravitation. We have accepted this assumption for a long time.
'There are good reasons for accepting it, good, sound mathematical reasons. Yet we have not empirically exhausted all possible means of detecting a gravitational field under such conditions, and it is foolish to exclude the possibility.
'So — Dykstra has made a good point in his fairly rigorous; demonstration that a mechanism such as Dunning's would demand the abandonment of the postulate of equivalence. It may well be that the postulate is an unwarranted assumption, based upon inadequate data. If so, that's a good starting point. What the next step might be, I don't know.'
'Is gravity a kind of a something that can be identified otherwise than as a mathematical symbol — or through the observation of a falling apple?'
'No. That's all it is, actually. A symbol in our formulas that stands for an unidentified something which manifests itself in the attraction between masses.'
'How about a flowing something, like this stream?5
'Could be. Nobody knows.'
The water eddied about a projecting rock near the bank. Berk threw in a handful of sticks he had been idly breaking, in his hand. Swiftly, they flowed together and converged in the centre of the whirlpool by the rock.
'Might be a point of view,' he said, 'in which it could be postulated that those sticks gravitated towards each other under a mutual attraction.'
'It wasn't attraction in them,' said Mart thoughtfully. 'It was forces pushing and pulling on them. Gravity — a pushing and pulling, maybe. But a pull or a push of what? That Dunning! He knew!'
Sitting on the porch in the dark, after dinner, Mart had a feeling of satisfaction, a vague sense of having accomplished something during the day. He didn't know what, but it didn't matter. It was something-
'You know,' he said suddenly, 'the thing we need to know, and that you psychologists ought to be able to tell us, is where ideas come from.
'Take the first cave man with two brain cells big enough to click together. Where did he get the idea to put a fire in his cave? I think that's the problem you and I tried to solve a long time ago. Where do they come from — inside or outside?' He paused and gave the mosquitoes his attention.
'Keep going,' said Berk.
'I haven't any further to go. I'm thinking about gravity again.'
'What are you thinking?'
'How to get a new idea concerning it. What does a man actually do when he cooks up a new theory, a new mechanism? I feel like I'm being sucked into that problem constantly, instead of the one I'm supposed to be attacking.'
'Well, what are you doing? You're trying to cook up a new idea-'
'I'm thinking right now about this afternoon. Something flowing — but it would be something you couldn't get a picture of- like space-time. Now that it's been brought into the open, I think I really have never liked the postulate of equivalence. Just a feeling knocking around through a few molecules in my cranium. The postulate is wrong.
'Then I try to picture something flowing through the dark of space. It couldn't be a three-dimensional flow like a river.'
He sat up straighter and slowly withdrew the cigar from his mouth. 'It couldn't be- But it could be a flow-' He stood up suddenly and turned towards the house. 'Look, Berk, you've got to excuse me, if you don't mind. I've got some maths to do.'
Berk's cigar tip brightened in a long, glowing moment. 'Don't mind me,' said the psychologist.
V
Berk had no idea what time Mart went to bed that night. In the morning he found him in the same position working furiously, and had the impression Mart had not retired at all. He observed he'd changed clothes, at least.
'The fish are calling,' said Berk.
Mart glanced up. 'Give me another half hour. Look, the fish can wait. I've got to get back to the office as soon as possible. There's something here I want to keep on with.'
Berk grinned agreeably. 'Go to it, boy. I'll get the car packed. You say when.'
In town he went directly to his own office without seeing anyone. There, he continued the work begun the night before. As he proceeded, some of his initial enthusiasm waned. It would be two or three days before he would be ready to invite inspection. One of his manipulations several pages back turned out to be in error. He retraced slowly through the maze.