06.06.2025
ary is a young, bright and brilliant scientist. She is happy, but lives in a sad and colorless reality: she has spent her whole life in a black and white room. Mary watched black and white television as a child and only knows SpongeBob and his friends in different shades of gray. As a teenager, she was often concerned that the different grays - slate gray, ash gray, cadet gray or light gray - of her clothes matched. Although her birthday cakes were always particularly delicious, with mango, raspberry, kiwi or cherry, they always looked the same - a mixture of black and white. And so, with each passing year of her life, Mary became more and more aware of her monochrome life.
Mary developed a desire to learn everything she could about color, whether it was its physical description or the physical processes responsible for our perception of color. Driven by these pursuits, Mary became the scientist we know today: She learned everything there is to know about colors. But she has never perceived colors herself. Her greatest dream, however, is still to be able to leave her room and experience a world that is not black and white.
The question I would like to ask you now is: Will Mary learn something new if she ever manages to leave her colorless room and step into the colorful world? Will her knowledge expand when she perceives colors herself for the first time?
This is the central question of this thought experiment.
Thought experiments are a means in philosophy to test ideas by mentally constructing and examining theoretical situations. The thought experiment described above is known as Mary’s Room.
The questions posed in a thought experiment do not have one single right or wrong answer. Because after all, finding the right answer is not the aim of a thought experiment. It would not be useful to simply say: "No! Mary doesn't learn anything new. That's the only correct answer!" Because we don't learn anything new from such an answer.
For us, as philosophers, it is much more interesting to critically examine the meaning of the given answer after we have answered the question intuitively for the first time. We want to examine exactly how the given answer teaches us about the world and ourselves. What are the implications of different answers? What do they mean for us, if anything, and how can we use them in our arguments?
If you answer the question with "Yes, Mary learns something new about the world.", then you have the same opinion as the inventor of this thought experiment, Frank Cameron Jackson. He was confident that this answer was the "obvious“ way to respond to the question posed.
According to Jackson, for example, when Mary sees a sun-yellow mango birthday cake in front of her for the first time on her next birthday, she will learn what it is like to perceive this sun-yellow. This is something she could never have learned in her colorless world, no matter how much she had already dealt with colors back then. By perceiving colors herself, she expands her knowledge, which was previously limited to physical facts, to non-physical facts. Colors are therefore more than pure physical facts.
This conclusion was so important for Jackson because he used this thought experiment as an argument against physicalism (physicalism is the thesis that the entire universe, including the mental, is purely physical). According to Jackson, the denial of physicalism is therefore unavoidable if the question posed in the thought experiment was answered with "Yes!" (which Jackson assumed).
However, it is equally possible to insist that Mary learns nothing new when she perceives colors for the first time. In this case, Mary knew exactly the same things in her black-and-white room, as she does outside of it, after eating her sunny-yellow birthday cake. Colors can therefore be fully understood through physical facts.
By trying to show that it is not "obvious" that Mary is learning something new, you can counter Jackson's argument against physicalism. Maybe you can come up with a good argument! Can the thought experiment perhaps be changed so that it is "obvious" that Mary is not learning anything new?
About the author: Ana Maria Abril won silver at the Philosophy Olympiad final in 2023. Now, she studies philosophy and mathematics in her native Bern and volunteers for the Philosophy Olympiad.
You could also try to counter Jackson's argument differently. For example, by arguing that the two answers suggested by the thought experiment (“Yes!” or “No!”) are not the only possible ones: Mary doesn't learn anything new, in the sense of new facts that she didn't know before. Rather, she learns a new skill when she leaves her room or when she sees the sunny-yellow mango cake in front of her for the first time.
When you do this, you bring up the question of whether we know, what we mean when we say, that someone learns something new. Different understandings of this can lead to different answers to the question in the thought experiment, which in turn can have different consequences. Perhaps we should therefore first examine what exactly we (should) understand by "Someone is learning something new" in order to be able to discuss the thought experiment in a meaningful way.
This raises the question of which other factors also play a role in how we answer the question of the thought experiment and may also need to be clarified first...
This thought experiment should have encouraged you to think and philosophize for yourself. It showed that philosophy is active: only when we think for ourselves and discuss our ideas with others do we really do what philosophy is all about. Perhaps your encounter with Mary in the thought experiment could even awaken the desire to leave your room and step further into the world of philosophy…. and participate in the Philosophy Olympiad!
