A Review of Physicalism

-Luuk Kuiper

Back, in the grim times of the middle ages religion and the church provided all the knowledge for the people. Their words where truth and their words only. In the modern-day religion’s task of providing truth has been mostly passed on to science. It is more than fair to say that we live in a world where science has become our primary source of information. Because of this knowledge is very often seen, in the west at least, as a purely physical thing and people often presuppose that physical knowledge could explain everything. The belief that reality can be fully explained by physical properties, and with that, the belief that non-physical properties do not exist, is called (reducible) physicalism. And in this essay, I would like to discuss if this belief is justified? 

And there so happens to be a famous thought experiment and corresponding argument that tries to problematize physicalism: The Knowledge Argument. The Knowledge Argument tries to establish that conscious experience relies not only on physical properties but also non-physical properties. It is one of the most prominent arguments against physicalism and was introduced in 1982 by philosopher Frank Jackson. He introduced The Knowledge Argument to show that there are non-physical aspects to experience. He did this through a thought experiment called ‘Mary’s Room’, also known as ‘Mary in the black and white room’ and it goes as follows:

Imagine a woman called Mary, she has lived in a black and white room all her life. She reads black and white books and all her electronics only display black and white. She has also studied neuroscience all her life. She is especially an expert on the subject of perception of colour in the brain. She knows all the physical facts about it, how light works in order to create the different colour wavelengths, the biological impact, et cetera. You could say that Mary is aware of all physical facts about colour and colour perception. Then after living all her life in black and white, her study is complete and she is handed an apple. And with that she sees the colour red for the very first time, and learns something new; what red looks like.

He concludes his thought experiment by stating:

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.
     –    Frank Jackson (1982)

He states that not all knowledge is physical, in other words, knowledge, in fact, relies on non-physical properties and thus everything can’t be explained by physical facts alone and thus physicalism is false. The non-physical knowledge referenced are called qualia. Qualia are things like the smell of ammonia or the feeling of being tickled. These things can be described but if described to a person who doesn’t experience any qualia, this theoretical being has been named a philosophical zombie, the person will never understand it; an example is trying to explain the smell of something to someone who can’t smell, or colour to a blind person.

So is modern (western) culture just blatantly wrong? Has the proof that society is wrong been available since 1982 and we’re just now finding out. Should we start rioting in our universities and throw the physicalist regime to the ground? Well, no. It would be a little hasty and dramatic to conclude this as we should always remain skeptical and that is what philosophers have done since 1982.

Others have argued that Mary would recognize the colors when seeing them based again on her complete physical knowledge. Her reaction to seeing the apple would be something along the lines of “oh, so this is red” and she wouldn’t learn anything new. However, philosopher Dennett argued an example called the blue banana trick. Arguing that the only reason why she would say “oh, so this is red” is because she would recognize the apple and know they are supposed to be red. And so if shown a blue banana she would say that it’s yellow. However the most common reaction to this argument is simply that she wouldn’t be fooled since she, you guessed it, has all the physical knowledge there is to acquire about colour.

Some philosophers have doubted the thought experiment itself. Pointing out that Mary could, in fact, imagine the colour experience because of her complete physical knowledge. In turn, the most common reaction to this argument by knowledge argument supporters is simply doubting the claim.

The knowledge argument makes a strong case against physicalism but it’s definitely not a closed and shut case. Jackson even changed sides on his own thought experiment. Stating that science could offer other explanations for the seeming difference in knowledge. Jacksons switch of side didn’t stop the pro-side from supporting the knowledge argument however. So it seems like the debate will probably rage on for years to come. This may not be a very satisfactory conclusion but I’d like to point out that the main takeaway from this discussion is that it’s important to remain skeptical about our presuppositions because they aren’t always as cut and dry as they seem. So stay skeptical.

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