[MEDICINE] Do we need eyes to see? – sensory perception and hallucination 😵‍💫

Our eyes are often credited with being central to our visual perception: a necessary transduction interface between the external world and the internal nervous system. But how much of vision really depends on this?

We could base this debate around dreaming: internally generated sensory experiences during the REM stage of sleep, when our eyes are closed. Dreams are internally constructed: there is no light going into our eyes that translates to what we see in the dream, which could indicate that perception of the world is more of an inside-out process rather than outside-in. Similarly, with hallucinations, the brain is able to generate a visual experience regardless of whether there is a signal from the eyes that has truly “seen” this set of light patterns in the external world. Therefore, conscious perception could be thought of as a series of controlled hallucinations: our brain internally generates visual experience in the occipital cortex, perhaps influenced by past experiences to make predictions, which the eyes then merely fine-tune, correcting any prediction error.

💡 Things to Consider

• Is the same true for other senses?: The framework of sensory processing is consistent between all 5 of our main senses: conscious perception is always in a respective cortical region. Auditory (sense of sound) hallucinations are famously noted in mental health conditions such as schizophrenia; and somatic (sense of touch, temperature, and proprioception) hallucinations can occur following amputation, termed phantom limb, where an individual experiences sensation in a body part that is no longer there.

• Blindsight: This term sounds like an oxymoron, but it quite effectively describes the experiences of some people with acquired blindness. In this state, there is no conscious perception of a visual stimulus (i.e. they cannot see), often due to dysfunction in the cortex of the brain. However, unconscious visual processing is preserved. In this way, the pupils still constrict when light intensity increases, sleep-wake cycles remain calibrated, and perhaps most remarkably, these individuals can “guess” how many fingers are being held up to them with statistically more accuracy than chance.

• Could we record our dreams?: During deep sleep, the thalamus (a key relay station in the brain between a sensory organ and the perception of its signal) becomes electrophysiologically synchronised with the cortex (where conscious experience is generated). This disconnects the cortex from the outside world and allows the cortex to “free-wheel” with generating sensory experiences. The question of whether it is possible to measure the electrical activity in the visual cortex and translate this into an image as a way to record dreams is yet to be answered…

🔎 Find out more

• Blindsight

  • Anil Seth - The Neuroscience of Reality

  • Blindsight - Scholarpedia

• Controlled hallucinations

  • Anil Seth - Your Brain Hallucinates Your Conscious Reality (TED Talk)

[LINGUISTICS] Do animals speak a language? 🐶

It has always been popularised in media that animals can ‘talk’, and that they have their own language just as humans do. Dr Doolittle certainly seems to think so. But is communication the same as language? What makes a language different from a communication tool? And how do we know what is really going on inside animals’ brains? 🧠 In order to answer this, we need to consider universal features of human languages, and whether we can identify these in animal-based communication systems, such as a bee’s waggle dance, a bird’s tweets, or whale songs. So, read on to find out whether your dog can really understand everything you’re saying. 🐶

💡 Things to Consider

• Chomsky: Noam Chomsky (a.k.a: the Godfather of Linguistics, and a name you will often hear in this newsletter, as well as in any Linguistics lecture at university!) often talks about the “Language Faculty”, the innate ability humans have to not only acquire language from a young age, but also interpret its lexicon and syntactical rules to spontaneously produce utterances. When you think about it, it’s pretty cool that we can produce sentences on the spot that we have never heard before. So, when people claim that their parrot can talk, it is really just repeating phrases it has already heard, without understanding the syntactic rules holding it together. Sorry to be a party pooper. Similarly, the claims that chimpanzees have been taught to manipulate grammatical rules to produce full “sentences” (Premack & Premack, 1972) are probably ignoring the fact that the chimpanzees are instead mimicking human behaviour and performing for the reward they received when they got it right. A disappointing, but realistic conclusion. Do you agree?

• Hockett: So, if we are saying that all human languages are different from animal communication, what characteristics prove this? A linguist called Charles Hockett came up with several “Design Features”, universal features shared by all human languages. Animal communication forms can have some, but not all of these features. One key concept is the notion of iconicity, the idea that there is an arbitrary relationship between the sounds used to represent a concept and its meaning. This might sound strange, but essentially means that there is nothing about the sounds /h/, /a/, /n/, and /d/ that relate to the meaning of “hand”. Another key feature is displacement, the capacity for a language to communicate ideas separate from the immediate time and place. I can talk about Australia in 2050, despite writing this from the UK in 2023.

• Bees: Consider the waggle dance, performed by bees to indicate the location and quantity of nectar. Is this a sort of language? It certainly conforms to the idea of displacement to some extent; the bees wag their tail to indicate when there is nectar further away. The bees can therefore communicate an idea that is separate from the immediate place of the “conversation”. But what about iconicity? Well, we know that bees make a larger circle when there is a bigger quantity of nectar, so clearly the relationship between the gesture and the meaning is not completely random. Where would you draw the line? When does communication become language?

[PHILOSOPHY] God and Omniscience: do I really have the freedom to choose what I have for breakfast? 🤔

Omniscience (knowing everything) is supposed to be one of God’s properties. Makes sense, right? You’d think that a supreme being should know absolutely everything: the meaning of life, where Ryan Gosling is right now, and what I’m going to have for breakfast tomorrow. However, this raises a lot of problems, which we are going to discuss below…

💡 Things to Consider

• Freedom and Foreknowledge: According to one plausible line of thought, God knows everything that will happen in the future (as he knows everything). This seems to imply that we don’t really have freedom in any substantial sense. Take, for example, my choice of brekkie for tomorrow morning. If God already knows what I’m going to have for breakfast, did I really have the free will to choose it? Of course, I had the two options in front of me, but if I was necessarily going to choose one over the other, it seems that my freedom isn’t freedom at all. What if God doesn’t know exactly what you’re going to pick, but knows you so well that he has a really good idea how you think and therefore what you’d be very likely to pick. How does this change the discussion?

• Immutability: Immutability is the property of being unchanging. Most people would argue that God is immutable: if God is the most perfect thing available, then why change, right? If I were God, I sure wouldn’t: if it ain’t broke, don’t fix it! But, omniscience seems to contradict with this property. How, you might ask? It’s all about God knowing something in particular that requires a change. Take, for example, the statement ‘the lesson is starting now’. We’ve all been there: we didn’t realise that it’s already 9am and we had the sudden fear of realising that the lesson is happening RIGHT NOW! For God to properly know this statement, it seemed that he would have to go from the state of not knowing something (i.e., that the lesson is now) to then knowing something. But hang on… I thought God knew everything, so how could he forget things like us silly humans?

• ‘Cambridge Changes’: Peter Geach makes the distinction between a real change, as opposed to what he calls a ‘Cambridge change’, which is not a real change at all. A Cambridge change occurs when a property is true of an object at one moment but is not true of it at the next moment, not because the object itself has changed, but because something around it has changed that makes a property true. For example, I could say that my friend Barnaby is taller than me, however - due to some miraculous tablets I bought from Amazon - the next moment, my height increased by a foot. After having digested said tablets, Barnaby is shorter than me. By the Cambridge criterion, Barnaby has changed, yet he has not undergone any real change, for in this case (unfortunately for him) he stayed at exactly the same height. So, I had undergone a real change, whilst Barnaby had undergone a Cambridge change. How can this be applied to the discussion of immutability?

🔎 Find out more

• Cambridge change (Wikipedia)

• Omniscience (Stanford Encyclopedia of Philosophy)

[FRENCH] Michel de Montaigne: On the Cannibals 🍖

Meet Michel de Montaigne (1533-1592), the OG philosopher of the French Renaissance (the cultural and artistic movement in France between the 15th and early 17th centuries - renaissance literally translates to ‘rebirth’!). He is probably most famous for dropping a collection of essays called Essais. In fact, he was the first person to describe his work as essays, or ‘attempts’ - think of the French verb essayer, which means ‘to try’!

On the Cannibals was one of these essays. Completed around 1580, the essay focuses on the ceremonies of the Tupinambá people in Brazil. Most notably, he described how tribes would engage in a ceremony of eating the bodies of their dead enemies as a matter of honour.

💡 Things to consider

• Irony: On the surface, many would see this as a simple essay that depicts these people as savages and barbarians. However, the essay has an undertone of irony, suggesting that Montaigne was critiquing the prevalent European perspectives on these ‘barbarians’, questioning why non-Europeans are automatically labeled as savage, highlighting the European tendency to use their society as a benchmark. Can his approach be considered a precursor to later Enlightenment concepts of universalism and cultural relativism?

• Colonialism: During Montaigne’s time, there existed considerable intrigue surrounding the 'New World' barbarians, particularly those encountered in present-day Brazil, where Villegaignon had landed in 1557. Montaigne clearly felt compelled to address this topic in the essay. Could Montaigne be suggesting that it is not the colonised who are the savages, but the colonisers?

• Christianity: During Montaigne’s time, something called the Wars of Religion was taking place in France. These were a series of conflicts between the Protestant and Catholic faction in France lasting 35 years. Throughout On the Cannibals, there is a semantic field of human body parts (it is an essay on cannibalism after all). Could this be an allusion to the Catholic practice of consuming the body and blood of Jesus after transubstantiation during communion? And, if so, does that mean Montaigne might be making a reference to the Wars of Religion, and calling the French people the real savages? It’s interesting to note that, during the war, people actually ended up practising cannibalism to survive during times of famine…

🗳️ Poll

👀 Keep your eyes peeled for…

• Aspire Webinar: Preparing for life at university

• Personal Statement Workshop | Undergraduate Study (cam.ac.uk)

• Introduction to Cambridge Applications | Undergraduate Study

• Livestream - MAT past test papers: 2009 & 2010