Professor Quillibrace was enjoying an unusually peaceful afternoon.
This should have made him suspicious.
Instead, he made another cup of tea.
There came a knock at the door.
"Come in."
Mr Blottisham entered wearing Wellington boots.
Professor Quillibrace slowly lowered his teacup.
"No."
Blottisham looked surprised.
"I've only just arrived."
"I know."
"You haven't asked where I'm going."
"I don't believe it will improve matters."
Miss Stray entered behind him.
She stopped.
Looked at the boots.
Looked at the wicker picnic hamper.
Looked at the folded map protruding from Blottisham's coat pocket.
"Oh."
she said.
Professor Quillibrace nodded sadly.
"Exactly."
Blottisham beamed.
"I thought we'd spend the afternoon in the quantum fields."
There was a silence of remarkable density.
Professor Quillibrace finally spoke.
"There are no Wellington boots in quantum field theory."
"There ought to be."
"Why?"
"The ground may be muddy."
"It has no ground."
Blottisham frowned.
"Then how does one reach the field?"
"There isn't one."
Miss Stray quietly sat down.
"I think this is going to require fresh tea."
Blottisham unfolded his map across the table.
It contained a careful sketch of rolling countryside.
Several areas were labelled:
Electron Field
Photon Meadow
Boson Copse
Higgs Pasture
One corner bore the helpful note:
PICNIC AREA (PROVISIONAL)
Professor Quillibrace stared at it.
"I particularly admire the stile."
"Thank you."
"What is beyond the stile?"
"The neutrino footpath."
Miss Stray laughed into her teacup.
Blottisham pointed enthusiastically.
"I thought we'd begin here."
He tapped the map.
"The Electron Field."
Professor Quillibrace sighed.
"There is no Electron Field."
Blottisham looked puzzled.
"Physicists mention it constantly."
"They do."
"So where is it?"
"It isn't a field."
"Then why call it one?"
Professor Quillibrace looked thoughtfully at the ceiling.
"I ask myself that rather often."
Miss Stray smiled.
"Perhaps because a field is something spread out."
Professor Quillibrace nodded.
"Continuous."
"Extending through space."
"Present everywhere."
Blottisham brightened.
"So there could still be sheep."
"No."
"Cows?"
"No."
"A scarecrow?"
"No."
"Wildflowers?"
"No."
"Professor..."
"Yes?"
"What, exactly, is wrong with this field?"
The room dissolved into laughter.
After several minutes Professor Quillibrace recovered.
"The metaphor highlights one feature."
"Which is?"
"That the thing is not localised like a particle."
"It extends."
"Yes."
"But unlike an ordinary field..."
"...it cannot be mown."
Blottisham crossed that off his notebook.
"No mowing."
"No grazing."
"No hedgerows."
"No."
Miss Stray looked thoughtfully at the map.
"I wonder whether the difficulty is that every field we've ever seen has soil."
Professor Quillibrace smiled.
"Quite."
"So the metaphor quietly imports..."
"...earth."
"...weather."
"...boundaries."
"...ownership."
"...fences."
"...and, apparently..."
He looked at Blottisham.
"...livestock."
Blottisham was unpacking the picnic hamper.
"I've brought sandwiches."
Professor Quillibrace looked alarmed.
"For whom?"
"In case we met anyone."
"In the quantum field?"
"One likes to be hospitable."
Miss Stray could no longer contain herself.
"I should very much like to know..."
she managed between laughs,
"...what sort of sandwiches you imagined a photon would prefer."
Blottisham considered.
"Cucumber."
Professor Quillibrace closed his eyes.
"I see."
"They're very light."
There was a long silence.
Miss Stray quietly applauded.
"I cannot decide..."
she said,
"...whether that is an excellent joke or a terrible one."
Professor Quillibrace opened one eye.
"At present..."
"...I lack the emotional resources to distinguish."
The conversation settled again.
Blottisham looked thoughtful.
"I think I've understood something."
Professor Quillibrace looked cautiously optimistic.
"Oh?"
"When physicists say 'field'..."
"Yes?"
"...they don't really mean field."
"Correct."
"They mean..."
Professor Quillibrace hesitated.
"...something that behaves in one important respect rather like a field."
"But not in most of the others."
"Exactly."
Blottisham nodded.
"So the metaphor is renting one characteristic."
Miss Stray smiled broadly.
"I like that."
"It doesn't buy the whole farm."
Professor Quillibrace laughed.
"No."
"It merely leases continuity."
The afternoon sun slanted across the windows.
Blottisham folded away the map.
"I've one final question."
Professor Quillibrace looked resigned.
"Naturally."
"If every point in space has quantum fields..."
"Yes?"
"...how do they know where one field ends and the next begins?"
Professor Quillibrace looked at Miss Stray.
Miss Stray looked at Professor Quillibrace.
Finally she answered.
"I don't think..."
she said gently,
"...they've been introduced."
Professor Quillibrace laughed so unexpectedly that he nearly spilled his tea.
The three gathered their things.
The Wellington boots remained by the door.
Unused.
The picnic was never eaten.
The sheep, if any had ever existed, remained entirely theoretical.
As they left the room, Miss Stray looked back at the abandoned map.
"It served its purpose."
"What purpose?"
asked Blottisham.
"It helped us discover precisely where the metaphor wandered off."
Professor Quillibrace nodded.
"And where the sheep should not."
Outside, the college lawns glowed in the afternoon sunshine.
Students crossed them freely.
Without once wondering whether they were traversing a quantum field.
Or whether somewhere, just beyond the hedge, a particularly philosophical photon was politely declining a cucumber sandwich.
No comments:
Post a Comment