Uploaded August 2026 | Updated September 2026, 2 weeks ago
#molyneux #molyneux #question #philosophy #perception #johnlocke
Full show notes at lovephilosophy.substack.com
An Irish scientist named William Molyneux sent philosopher John Locke a letter in 1688. That letter had a question in it that people are still talking about today. Suppose a person is born blind and has learned by touch to tell a cube from a sphere. If a surgery gives that person sight, and the two objects are set on the table in front of him, could that person tell, just by looking alone, which is the sphere and which is the cube?
Locke said no, and put the question into the second edition of his Essay Concerning Human Understanding. Berkeley said no more emphatically. Leibniz said yes, but as you’ll hear, there’s a catch. Three centuries later the question is still open…but now it’s made it’s way into scientific labs.
Janet Levin and Brian Glenney have been in conversation about this problem since Brian’s dissertation defense in 2007, where Janet was on his committee. They still disagree (productively) about some aspects but their combined work seems to also be offering a new view on many of these old rationalist vs. empiricist issues.
Guests
Janet Levin is recently retired from the philosophy department at the University of Southern California. She works on the mind-body problem, phenomenal concepts, and what she calls the philosophy of philosophy: whether thought experiments are worth anything, and whether they can absorb empirical information and still count as philosophy. Her 2008 paper introduced the distinction between temporal and epistemic immediacy that has shaped how the Molyneux question is tested ever since.
Brian Glenney teaches at Norwich University in Vermont. He wrote his dissertation on Molyneux’s problem at USC in 2007 under James Van Cleve and Janet Levin, wrote the Internet Encyclopedia of Philosophy entry on the question, and has since argued for a pluralist answer — that the question has many correct answers depending on who is being asked about, and how. He also works on skateboarding, urban space, and the sensory expertise he calls the skater’s eye.
00:00 — Why a navigational approach to mind keeps running into this question
02:20 — Introductions: phenomenal concepts, sensory expertise, and Bernie at the skate park
05:20 — Janet reads Locke’s own statement of the question, and his answer
08:00 — Why this was supposed to be the crucial experiment for empiricism vs. rationalism
10:30 — The 1688 letter Locke never answered, and the 1693 one he did
12:00 — Molyneux, Dioptrica Nova, and the attempt to give empiricism experimental oomph
14:00 — Why Locke buried the question in a passage about perceptual learning
15:00 — Common sensibles: what touch and sight might share
17:00 — Locke’s “at first sight” trick, and what it forecloses
19:30 — Passivity vs. activity: if you move your head, is it still perception?
20:40 — Leibniz’s cheat code, and the birth of epistemic immediacy
22:20 — Janet’s distinction: temporal immediacy vs. epistemic immediacy
24:15 — Held (2011) and the best evidence for a “no”
27:30 — Andrea’s caricature: two languages, or one idea?
29:30 — Why restored vision isn’t normal vision — and the paradox that follows
31:00 — Vision and touch as English and Russian; Leibniz as the bilingual child
33:30 — Janet on phenomenal concepts and why Molyneux caught her
35:40 — Did you know Adam Smith had a theory of perception? He wrote it at fifteen
37:50 — Brian finds his own ancestor in the archive: George Glenny, Aberdeen, 1796
40:15 — The moon illusion, and how Janet and Brian actually met
41:20 — The dissertation with six chapters, and the one revision that changed everything
42:30 — Maybe there isn’t a single correct answer
47:15 — Project Prakash: five subjects, three days of play, and a fast yes
51:30 — Janet’s counter-proposal: what if you only tweak vision?
55:20 — Bumpy pacifiers, baby chicks, and the ten-hour-old infants who disagree
58:50 — The six-month-old who recognizes its own hand
01:01:00 — Nobody frames it as empiricism vs. rationalism anymore
01:03:20 — The couch potato perceiver and the sentient statue
01:05:50 — Could virtual reality run the experiment we can’t?
01:07:00 — Path dependency: every subject arrives with a history
01:11:20 — The blind Rubik’s Cube puzzler, and whether expertise transfers
01:15:00 — “Give me something I care about”: motivation as the missing variable
01:19:10 — Why does perception have to be passive at all?
01:22:20 — Andrea: what if it isn’t yes or no?
01:26:50 — Ned Block and the border between seeing and thinking
01:29:20 — The skater’s eye: knowledge in the heel rather than the head
01:33:00 — Enactivism, affordances, and the motivation Brian adds to them
01:36:30 — Janet puts a lock on the back gate
01:39:20 — Do you still care about this? Plato’s cave, Reid, and the seduction of the external world
#andreahiott
loveandphilosophy.com
#molyneux #molyneux #question #philosophy #perception #johnlocke
Full show notes at lovephilosophy.substack.com
An Irish scientist named William Molyneux sent philosopher John Locke a letter in 1688. That letter had a question in it that people are still talking about today. Suppose a person is born blind and has learned by touch to tell a cube from a sphere. If a surgery gives that person sight, and the two objects are set on the table in front of him, could that person tell, just by looking alone, which is the sphere and which is the cube?
Locke said no, and put the question into the second edition of his Essay Concerning Human Understanding. Berkeley said no more emphatically. Leibniz said yes, but as you’ll hear, there’s a catch. Three centuries later the question is still open…but now it’s made it’s way into scientific labs.
Janet Levin and Brian Glenney have been in conversation about this problem since Brian’s dissertation defense in 2007, where Janet was on his committee. They still disagree (productively) about some aspects but their combined work seems to also be offering a new view on many of these old rationalist vs. empiricist issues.
Guests
Janet Levin is recently retired from the philosophy department at the University of Southern California. She works on the mind-body problem, phenomenal concepts, and what she calls the philosophy of philosophy: whether thought experiments are worth anything, and whether they can absorb empirical information and still count as philosophy. Her 2008 paper introduced the distinction between temporal and epistemic immediacy that has shaped how the Molyneux question is tested ever since.
Brian Glenney teaches at Norwich University in Vermont. He wrote his dissertation on Molyneux’s problem at USC in 2007 under James Van Cleve and Janet Levin, wrote the Internet Encyclopedia of Philosophy entry on the question, and has since argued for a pluralist answer — that the question has many correct answers depending on who is being asked about, and how. He also works on skateboarding, urban space, and the sensory expertise he calls the skater’s eye.
00:00 — Why a navigational approach to mind keeps running into this question
02:20 — Introductions: phenomenal concepts, sensory expertise, and Bernie at the skate park
05:20 — Janet reads Locke’s own statement of the question, and his answer
08:00 — Why this was supposed to be the crucial experiment for empiricism vs. rationalism
10:30 — The 1688 letter Locke never answered, and the 1693 one he did
12:00 — Molyneux, Dioptrica Nova, and the attempt to give empiricism experimental oomph
14:00 — Why Locke buried the question in a passage about perceptual learning
15:00 — Common sensibles: what touch and sight might share
17:00 — Locke’s “at first sight” trick, and what it forecloses
19:30 — Passivity vs. activity: if you move your head, is it still perception?
20:40 — Leibniz’s cheat code, and the birth of epistemic immediacy
22:20 — Janet’s distinction: temporal immediacy vs. epistemic immediacy
24:15 — Held (2011) and the best evidence for a “no”
27:30 — Andrea’s caricature: two languages, or one idea?
29:30 — Why restored vision isn’t normal vision — and the paradox that follows
31:00 — Vision and touch as English and Russian; Leibniz as the bilingual child
33:30 — Janet on phenomenal concepts and why Molyneux caught her
35:40 — Did you know Adam Smith had a theory of perception? He wrote it at fifteen
37:50 — Brian finds his own ancestor in the archive: George Glenny, Aberdeen, 1796
40:15 — The moon illusion, and how Janet and Brian actually met
41:20 — The dissertation with six chapters, and the one revision that changed everything
42:30 — Maybe there isn’t a single correct answer
47:15 — Project Prakash: five subjects, three days of play, and a fast yes
51:30 — Janet’s counter-proposal: what if you only tweak vision?
55:20 — Bumpy pacifiers, baby chicks, and the ten-hour-old infants who disagree
58:50 — The six-month-old who recognizes its own hand
01:01:00 — Nobody frames it as empiricism vs. rationalism anymore
01:03:20 — The couch potato perceiver and the sentient statue
01:05:50 — Could virtual reality run the experiment we can’t?
01:07:00 — Path dependency: every subject arrives with a history
01:11:20 — The blind Rubik’s Cube puzzler, and whether expertise transfers
01:15:00 — “Give me something I care about”: motivation as the missing variable
01:19:10 — Why does perception have to be passive at all?
01:22:20 — Andrea: what if it isn’t yes or no?
01:26:50 — Ned Block and the border between seeing and thinking
01:29:20 — The skater’s eye: knowledge in the heel rather than the head
01:33:00 — Enactivism, affordances, and the motivation Brian adds to them
01:36:30 — Janet puts a lock on the back gate
01:39:20 — Do you still care about this? Plato’s cave, Reid, and the seduction of the external world
#andreahiott
loveandphilosophy.com
