Qualia, Butyrate, and Aged Cheese

One of the most common arguments in philosophy of mind is the “inverted spectrum” argument. Perhaps my experience of red is completely different from yours. Perhaps what I call red is what you would call blue. Since we cannot directly compare subjective experience, the argument goes, we cannot know.

I suspect this is largely the wrong way to think about qualia.

Humans share remarkably similar sensory systems, neural architectures, bodies, and evolutionary histories. We may not experience the world identically, but there are strong reasons to expect substantial overlap. My red is probably very similar to your red. Not because we can prove it directly, but because the underlying machinery generating the experience is so similar.

Smell provides an interesting window into this question.

Consider butyric acid. In isolation it is associated with rancid butter and vomit. Yet it is also an important component of many aged cheeses. The molecule has not changed. The experience has.

The same principle applies to putrescine and related compounds. Putrescine is associated with decay and decomposition. Most people find concentrated sources of these compounds unpleasant. Yet small amounts occur naturally in a variety of fermented and aged foods that many people enjoy.

This creates a problem for simplistic theories of qualia.

If pleasantness and unpleasantness were intrinsic properties of molecules, the same molecule should always produce the same experience. Instead, context dramatically changes the resulting feeling.

A molecule enters a much larger system:

odor → category → memory → expectation → bodily state → prediction → experience

The smell is not experienced in isolation. It becomes embedded within a global model.

A strong concentration of putrescine in a dead animal activates a model involving contamination, disease risk, avoidance, and disgust. The same compound, present at trace levels within an aged cheese, participates in an entirely different model involving food, nutrition, anticipation, social context, and reward.

The resulting qualia are different because the model is different.

This suggests that qualia may not be properties of stimuli. They may be properties of model states.

The smell itself is merely an input. The experience emerges from the network of associations activated by that input.

This observation extends beyond smell.

A cat may treat a string as a snake. An octopus may carry a coconut shell across an exposed seafloor because it contains a model of a future self encountering future danger. A scrub jay may relocate hidden food because it models what another bird knows.

In each case, behavior is driven not by raw sensory input but by internal models.

My own suspicion is that consciousness arises when these models become integrated into a global model of experience which recursively monitors itself. Awareness is not merely sensing. Awareness is attention directed toward the modeling process itself.

Within this framework, qualia become less mysterious.

“What is it like?” is not answered by examining the stimulus. It is answered by examining the state of the global model.

The smell of aged cheese and the smell of decay may share molecules, but they occupy different locations within the model. The resulting experiences differ because the surrounding associations differ.

Qualia are therefore neither arbitrary nor perfectly universal.

They form overlapping clusters shaped by shared biology, shared evolution, and individual experience. Most humans probably inhabit very similar regions of experiential space. The edges are soft, but the overlap is substantial.

My red is probably very similar to your red.

And the smell of aged cheese may help explain why.