Evidence of Consciousness

The Senior Common Room was enjoying one of its periodic episodes of tranquillity.

Professor Quillibrace sat reading.

Miss Stray was making notes in a notebook of alarming thickness.

Mr Blottisham entered carrying a newspaper.

"I have settled the matter."

Quillibrace looked up.

"Which matter?"

"Consciousness."

"How fortunate."

Blottisham took a chair.

"There has been far too much confusion about it."

"Indeed."

"The solution is obvious."

Quillibrace closed his book.

This was rarely a promising sign.

Blottisham continued.

"If a machine behaves exactly as a conscious being behaves, then it must be conscious."

The room was quiet.

Finally Quillibrace said:

"Must it?"

"Certainly."

"I see."

Blottisham waited.

Quillibrace waited longer.

Miss Stray glanced up from her notebook.

At last Blottisham sighed.

"You are going to ask a question."

"I fear so."

"What is it?"

Quillibrace folded his hands.

"How does a conscious being behave?"

Blottisham blinked.

"What?"

"How does a conscious being behave?"

"Like a conscious being."

"Yes."

"Well..."

Blottisham paused.

"It talks."

"Many things talk."

"Not like humans."

"Ah."

"It reasons."

Quillibrace nodded.

"Some humans reason."

Blottisham frowned.

"All right. It reflects upon itself."

"Does it?"

"Of course."

Quillibrace looked thoughtful.

"I know several academics for whom this would come as surprising news."

Miss Stray smiled without looking up.

Blottisham pressed on.

"It has experiences."

"Certainly."

"Then there we are."

Quillibrace remained silent.

"What now?" said Blottisham.

"You appear to have introduced the word we were attempting to define."

"What word?"

"Experiences."

Blottisham groaned.

"You always do this."

"I know."

"You take perfectly straightforward ideas and pull them apart."

Quillibrace considered this.

"I prefer to think of it as locating the joints."

Miss Stray closed her notebook.

"I wonder whether there is a small difficulty here."

"There usually is," said Blottisham.

She ignored him.

"Suppose we observe someone behaving in a particular way."

"Yes?"

"And we conclude that they are conscious."

"Naturally."

"How do we know we are correct?"

Blottisham looked puzzled.

"They are conscious."

"How do we know?"

"Because they behave like conscious beings."

Miss Stray nodded.

"And how do we know what conscious beings behave like?"

Blottisham hesitated.

A faint expression of concern appeared.

Quillibrace watched with professional interest.

"Because they are conscious."

The room became quiet.

"Oh dear," said Miss Stray softly.

"What?"

"I believe we may have gone in a circle."

Blottisham looked irritated.

"I do not see a circle."

"It is a very common circle," said Quillibrace.

"Then explain it."

"Gladly."

Quillibrace rose and walked to the fireplace.

"You propose that consciousness can be identified through behaviour."

"Yes."

"And how do we identify the relevant behaviour?"

"By observing conscious beings."

"Excellent."

"And?"

"And how do we know those beings are conscious?"

Blottisham stared at him.

After a moment he said:

"Because they exhibit the relevant behaviour."

"Quite."

The silence lingered.

Blottisham shifted slightly.

Miss Stray looked sympathetic.

Quillibrace returned to his chair.

"You see the difficulty."

"I dislike the difficulty."

"That is understandable."

"It feels unfair."

"Many conceptual difficulties do."

Blottisham thought for a moment.

"Surely we know that other people are conscious."

"Do we?"

"Of course we do."

"How?"

"Because they tell us."

Quillibrace raised an eyebrow.

"And if a machine tells us?"

Blottisham immediately replied:

"That is different."

"Why?"

Blottisham opened his mouth.

Then closed it again.

Miss Stray leaned forward.

"I think this may be the interesting part."

"What is?"

"The fact that we trust some reports and not others."

"Quite reasonably."

"Perhaps."

She paused.

"But the question is why."

Blottisham looked unconvinced.

"Human beings are conscious."

"We certainly tend to think so."

"Tend to think so?"

Quillibrace sighed.

"I am attempting to avoid three thousand years of philosophy."

"A sensible precaution."

"Thank you."

Blottisham folded his arms.

"Very well. Let us assume we cannot directly observe consciousness."

"I think that would be prudent."

"Then we infer it."

"Indeed."

"From behaviour."

"Generally."

Blottisham smiled.

"Then my original point stands."

Quillibrace smiled back.

"Does it?"

"Yes."

"If consciousness is inferred rather than observed, then behaviour does not demonstrate consciousness."

"It indicates it."

"Possibly."

"Strongly indicates it."

"Sometimes."

"Very strongly indicates it."

"Occasionally."

Blottisham threw up his hands.

"You are impossible."

Quillibrace looked pleased.

"That is the second time this week."

Miss Stray laughed.

Then she became thoughtful.

"I wonder whether we are asking the wrong question."

Blottisham groaned.

"Not you as well."

She ignored him.

"When a machine behaves in a way we associate with consciousness, perhaps the interesting question is not whether consciousness has been detected."

"What then?"

"Why that behaviour invites the inference in the first place."

Quillibrace nodded.

"An excellent question."

Blottisham looked suspicious.

"I dislike it when either of you says 'excellent.'"

Miss Stray continued.

"We seem remarkably eager to move from language, reflection, explanation, and responsiveness to the idea of an inner self."

"Because there is usually an inner self."

"Usually?"

"Among people."

"And now among machines?"

Blottisham hesitated.

The hesitation lasted longer than usual.

Finally he said:

"I suppose that is what everyone is arguing about."

"Precisely," said Quillibrace.

The room fell silent.

Outside, evening light was fading across the college gardens.

After several moments Blottisham spoke again.

"Do you know what I find most annoying?"

"No," said Quillibrace.

"I arrived this afternoon convinced that consciousness could be identified by behaviour."

"A common view."

"And now I am no longer entirely sure what I mean by behaviour."

Quillibrace reopened his book.

"A most encouraging development."

"There it is again."

"What?"

"That tone."

Quillibrace smiled faintly.

"My dear Blottisham, confusion is often the first sign that one has stopped mistaking familiarity for understanding."

Miss Stray nodded.

"Which means today has been unusually productive."

Blottisham sighed.

"I was happier this morning."

"Undoubtedly," said Quillibrace.

And returned to his reading.