#knowledge-argument — Public Fediverse posts on home.social

What does the knowledge argument actually demonstrate?

The argument, which shows up in various forms in numerous philosophical papers and thought experiments, is that we can have a complete physical understanding of a conscious being, but still not know how it feels to be that being. We can know everything about a bat’s nervous system, Thomas Nagel argues, but still not know what it’s like to be a bat. The usual implication is that there must be something non-physical involved.

Maybe the most famous thought experiment on this is Mary’s Room, which I posted about a few years ago. However, that post was in the context of sharing a video, and so was a bit cursory, although it sparked a good discussion at the time. My views, although still similar, may have clarified a bit, so it feels like time for a fresh take.

In case you’re not already familiar with it, here’s a quote of Frank Jackson’s original description via the Stanford Encyclopedia article on the subject:

Mary is a brilliant scientist who is, for whatever reason, forced to investigate the world from a black and white room via a black and white television monitor. She specializes in the neurophysiology of vision and acquires, let us suppose, all the physical information there is to obtain about what goes on when we see ripe tomatoes, or the sky, and use terms like ‘red’, ‘blue’, and so on. She discovers, for example, just which wavelength combinations from the sky stimulate the retina, and exactly how this produces via the central nervous system the contraction of the vocal chords and expulsion of air from the lungs that results in the uttering of the sentence ‘The sky is blue’.… What will happen when Mary is released from her black and white room or is given a color television monitor? Will she learn anything or not? It seems just obvious that she will learn something about the world and our visual experience of it. But then is it inescapable that her previous knowledge was incomplete. But she had all the physical information. Ergo there is more to have than that, and Physicalism is false.

I think it pays to untangle two takeaways from this description. One is that there are some things that can only be known through experience. The second, Jackson’s main conclusion, is that experience is non-physical. The second takeaway is quicker to resolve, so I’ll address it first.

We can summarize the argument with these two points.

Mary has all the physical information on color perception prior to experiencing color.
When Mary experiences color for the first time, she learns new information.

The conclusion is that the new information Mary learns cannot be physical, since she already had all the physical information. However, the argument about physicalism seems circular. It appears to presuppose its conclusion. To see the implicit assumption, imagine we have the same description, but without any reference to what information is or isn’t physical.

Mary has all the information on color perception prior to experiencing color.
When Mary experiences color for the first time, she learns new information.

With the change, the premises become contradictory. How can she learn new information if she had all the information?

But what if we assume physicalism and change the description accordingly?

Mary has all the physical information on color perception prior to experiencing color.
When Mary has the physical experience of color for the first time, she learns new physical information.

Again, we end up with a contradiction. The premises only seem consistent by assuming the purported conclusion, that experience is non-physical. So, this part of the argument seems like a fail, and there are no implications for physicalism.

Okay, but what about the first takeaway, that there are some things that can only be known through experience?

Most people, whether they agree about the non-physical part, actually do think Mary learns something new when she experiences color for the first time. This revised view of the premise is that she had all the third person information that could ever be obtained about color perception, prior to experiencing it.

The question is, what is the new information she learns? It doesn’t seem like anyone can say what it is, other than referencing her experience of color in various synonymous ways, such as finding out what it’s like to experience color, having the mental qualities of color, acquiring phenomenal knowledge of color, etc. This fits since the redness of red is supposed to be private and ineffable. If anyone actually could describe it, Mary would have read their description and would know what to expect.

Some philosophers argue that she doesn’t acquire new propositional knowledge, just new abilities, the ability to remember, imagine, and recognize colors. Whether this argument works might depend on what we mean by “knowledge”.

What I think we can say is that Mary’s nervous system is allowed to discriminate colors for the first time. Her neural circuitry is exercised in a new way. And she is subsequently able to remember the discrimination.

But could she have imagined the discrimination prior to experiencing it? Would she be able to recognize her first experience of red or blue? Intuitively, it’s hard to see how she could.

However, imagine if someone slides a color spectrum chart under the door, and it becomes her first color experience. The version they provide has no labels for any of the colors or wavelengths. To be let out of the room, Mary is told she must identify red and blue on the chart.

Click through for image source and credit

Would she be able to do it? Again, intuitively, it might seem hopeless. However, consider what’s currently known about colors and perception. Mary knows the relationship between the colors, so that violet is adjacent to blue, which is next to cyan, followed by greens, yellows, oranges, reds, etc. She also knows that the reds, oranges, and yellows would jump out to her and be more distinct than the greens, blues, and violets. Maybe she couldn’t get the exact colors right, but it seems like logical deduction could get her in the ballpark.

Her captors can make it harder if they instead present her with a possibly inverted color wheel, or just give her the colors in isolated patches. It still seems like she could work out the relationships, even if she had to cut up and rearrange the various colors. The hardest case might be if they just give her one isolated color patch and demand she name it. Distinguishing your very first blue from green, or orange from red, seems hard to imagine. (And hardly seems fair given that lifelong color perceivers can’t always agree either.)

But remember, this is all based on a little bit of what we know today. Mary’s knowledge is supposed to be far more complete. In our revised understanding of the premises, she has all the third person information that will ever be obtainable. Given where current knowledge gets us, it’s plausible her far more complete information leaves little, if anything, for her to learn.

Can we say that beyond all doubt? No, because we don’t have Mary’s described level of knowledge, or what it might entail. And for all practical purposes, it probably isn’t feasible for her to ever really know enough to be impervious to learning something new.

But she would expect ripe strawberries, roses, and blood to have similar hues, as well as daffodils, bananas, and the sun. She would anticipate the sky and deep water having similarities, as well as leaves, grass, and emeralds. And as noted above, she would expect some colors to jump out more than others. She would anticipate the unease typically caused by walking into a red room. In other words, she would recognize a lot more in the experience than people commonly assume.

So it doesn’t seem like the knowledge argument works against physicalism. And it seems to overstate the case for experience being private and ineffable, at least in any absolute sense.

Unless of course I’m missing something. Are there consequences for physicalism here I’m overlooking? Would Mary have more challenges identifying colors than I’m thinking? Or would there be ways, even with current knowledge, she’d be able to confidently identify even the isolated patch?

https://selfawarepatterns.com/2024/09/21/the-problem-with-the-knowledge-argument/

#Consciousness #knowledgeArgument #MarySRoom #PhilosophyOfMind #physicalism #Qualia