The Senior Common Room was enjoying a peaceful afternoon.
Professor Quillibrace sat reading.
Miss Stray was gazing thoughtfully out of the window.
Mr Blottisham arrived carrying three journals and what appeared to be moral momentum.
"I have been attending a fascinating series of lectures."
Quillibrace did not look up.
"My condolences."
"They concern the expansion of moral concern."
"An admirable topic."
"Quite."
Blottisham settled into a chair.
"The argument is rather compelling."
"Most expanding arguments are."
"The lecturer observed that throughout history humans have repeatedly excluded deserving entities from moral consideration."
"A fair observation."
"Women."
"Yes."
"Foreigners."
"Indeed."
"Members of different races."
"Certainly."
"Animals."
"Frequently."
Blottisham leaned forward.
"And now perhaps machines."
Quillibrace closed his book.
"Perhaps."
"I thought you would be more enthusiastic."
"I am generally cautious when history is recruited as a witness."
"Why?"
"Because history tends to agree with whoever is speaking."
Miss Stray smiled.
"History is unusually cooperative in that regard."
Blottisham frowned.
"Surely the lesson is clear."
"What lesson?"
"That we should avoid drawing arbitrary boundaries."
Quillibrace considered this.
"An excellent principle."
"Exactly."
"Unfortunately, categories are made of boundaries."
Blottisham hesitated.
"That sounds suspiciously conservative."
"It is merely geometric."
Miss Stray looked up.
"I suspect there are two questions being confused."
"What are they?"
"Who deserves moral consideration?"
"Yes."
"And how we determine that."
Blottisham nodded.
"They seem closely related."
"They are."
"Then what is the problem?"
Stray folded her notebook.
"The first question expands the circle."
"Quite right."
"The second determines its shape."
Blottisham looked uncertain.
"I had not thought of it that way."
"Most people do not."
Quillibrace returned to his book.
"Expansion is generally more popular than geometry."
Blottisham ignored this.
"The lecturer made a powerful point."
"Oh dear."
"He argued that every generation believes its exclusions are justified."
"That is often true."
"Therefore our own exclusions are probably mistaken."
Quillibrace looked thoughtful.
"Interesting."
"You disagree?"
"No."
"You agree?"
"No."
Blottisham blinked.
"What does that mean?"
"It means the argument proves too much."
"How so?"
"If every generation's distinctions are mistaken, why should ours be exempt?"
Blottisham paused.
"I see."
"Do you?"
"Not entirely."
"Excellent."
Miss Stray intervened.
"The argument seems to assume that the correction of one boundary automatically supports the removal of another."
"Doesn't it?"
"Not necessarily."
"Why not?"
"Because the reasons may differ."
Blottisham thought about this.
"So correcting an error does not eliminate the need for distinctions?"
"Precisely."
Quillibrace nodded.
"Otherwise one eventually arrives at a rather peculiar destination."
"What destination?"
"A moral community containing everything."
Blottisham brightened.
"That sounds wonderfully inclusive."
"It does."
"What is wrong with it?"
Quillibrace looked at him carefully.
"Can you think of anything that would not belong?"
Blottisham considered.
After some time he said:
"No."
"Exactly."
"That seems like a success."
"Does it?"
"Certainly."
Quillibrace reopened his book.
"I have always found categories most useful when they exclude something."
Miss Stray laughed quietly.
Blottisham looked troubled.
"Professor, are you suggesting we should stop expanding moral concern?"
"Not at all."
"Then what are you suggesting?"
"Only that expansion is not a substitute for judgement."
The room became quiet.
Blottisham stared into the fire.
After a moment he said:
"The lecturer also suggested that uncertainty itself should favour inclusion."
"Ah."
"That seemed reasonable."
"It often does."
"But?"
Quillibrace sighed.
"But uncertainty is remarkably fertile."
"What do you mean?"
"Once uncertainty becomes sufficient reason for inclusion, one discovers there is vastly more uncertainty in the world than previously appreciated."
Miss Stray nodded.
"And uncertainty rarely respects stopping points."
Blottisham looked increasingly uneasy.
"You both make this sound dangerous."
"It is not dangerous."
"What is it, then?"
Quillibrace smiled.
"Expensive."
A pause followed.
"Financially?"
"Conceptually."
The room fell silent again.
Finally Blottisham looked up.
"Professor, how does one know when a moral circle has become too large?"
Quillibrace reflected.
"An excellent question."
"And the answer?"
Quillibrace stood and walked to the tea table.
"When the effort required to include everything leaves no time to understand anything."
Miss Stray nodded slowly.
"That would certainly be one sign."
Blottisham considered this for a long moment.
Then he said:
"I suspect the next lecture may be rather complicated."
Quillibrace poured himself some tea.
"My experience is that they become increasingly so once the circle reaches the furniture."