| 20914 | The directive centre is located in the whole head [Democritus, by Ps-Plutarch] |
| Full Idea: Democritus says [the directive centre is located] in the whole head. | |
| From: report of Democritus (fragments/reports [c.431 BCE], A105) by Pseudo-Plutarch - On the Doctrine of the Philosophers 4.5.1 | |
| A reaction: The whole head is not quite the brain, but he is getting very warm indeed, and long before anyone else got so close. |
| 13154 | Do we think and experience with blood, air or fire, or could it be our brain? [Plato] |
| Full Idea: Is it with the blood that we think, or with the air or the fire that is in us? Or is it none of these, but the brain that supplies our senses of hearing and sight and smell. | |
| From: Plato (Phaedo [c.382 BCE], 097a) | |
| A reaction: In retrospect it seems surprising that such clever people hadn't worked this one out, given the evidence of anatomy, in animals and people, and given brain injuries. By the time of Galen they appear to have got the answer. |
| 23218 | The brain has no responsibility for sensations, which occur in the heart [Aristotle] |
| Full Idea: And of course, the brain is not responsible for any of the sensations at all. The correct view is that the seat and source of sensation is the region of the heart. | |
| From: Aristotle (The Parts of Animals [c.345 BCE]), quoted by Matthew Cobb - The Idea of the Brain 1 | |
| A reaction: [Need a reference] Hippocrates's assertion a century earlier made no impression on the great man. I wish he had been a little more circumspect with his own view. |
| 23219 | Stopping the heart doesn't terminate activity; pressing the brain does that [Galen, by Cobb] |
| Full Idea: Even when an animals heart was stopped [by hand] it continued its muted whimpers, …but when the brain was pressed the animal stopped making a noise and became unconscious. | |
| From: report of Galen (The soul's dependence on the body [c.170]) by Matthew Cobb - The Idea of the Brain 1 | |
| A reaction: It's not that the ancients didn't do science. It's that ancient people paid no attention to what their scientists discovered. |
| 24027 | Nerves and movement originate in the brain, where imagination moves them [Descartes] |
| Full Idea: The motive power or the nerves themselves originate in the brain, which contains the imagination, which moves them in a thousand ways, as the common sense is moved by the external sense. | |
| From: René Descartes (Rules for the Direction of the Mind [1628], 12) | |
| A reaction: This sounds a lot more physicalist than his later explicit dualism in Meditations. Even in that work the famous passage on the ship's pilot acknowledged tight integration of mind and brain. |
| 7882 | Researching phenomenal consciousness is peculiar, because the concepts involved are peculiar [Papineau] |
| Full Idea: It is a mistake to suppose that research into phenomenal consciousness can proceed just like other kinds of scientific research. Phenomenal concepts are peculiar, and some of the questions they pose for empirical investigation are peculiar too. | |
| From: David Papineau (Thinking about Consciousness [2002], 7.01) | |
| A reaction: This arises from Papineau's Conceptual Dualism, that our concepts are deeply dualist, when the underlying ontology is not. Brain researchers are wise to ignore phenomenology, and creep slowly forward from the physical end, where the concepts are clear. |
| 2952 | A 1988 estimate gave the brain 3 x 10-to-the-14 synaptic junctions [Lockwood] |
| Full Idea: It is estimated by Gierer (1988) that the human cerebral cortex alone contains about 300,000,000,000,000 synaptic junctions. | |
| From: Michael Lockwood (Mind, Brain and the Quantum [1989], p.46) | |
| A reaction: As we grasp the vastness of this number, and the fact that the junctions are all active, the idea that a brain does something astonishing is not quite so surprising. |
| 4902 | Pain doesn't have one brain location, but is linked to attention and emotion [Carter,R] |
| Full Idea: Scans show there is no such thing as a pain centre; pain springs mainly from the activation of areas associated with attention and emotion. | |
| From: Rita Carter (Mapping the Mind [1998], p. 12) | |
| A reaction: Most brain research points to the complex multi-layered nature of experiences that were traditionally considered simple. We can be distracted from a pain, and an enormous number of factors can affect our degree of dislike of a given pain. |
| 4904 | Proper brains appear at seven weeks, and neonates have as many neurons as adults do [Carter,R] |
| Full Idea: The main sections of the brain, including the cerebral cortex, are visible within seven weeks of conception, and by the time the child is born the brain contains as many neurons - about 100 billion - as it will have as an adult. | |
| From: Rita Carter (Mapping the Mind [1998], p. 17) | |
| A reaction: Of interest in the abortion debate, and also in thinking about personal identity. However, it seems clear that the number of connections, rather than neurons, is what really matters. A small infant may well lack personal identity. |
| 4915 | In primates, brain size correlates closely with size of social group [Carter,R] |
| Full Idea: Brain size in primates is closely associated with the size of the social group in which the animal lives. | |
| From: Rita Carter (Mapping the Mind [1998], p.257) | |
| A reaction: Intriguing. Humans can have huge social groups because of language, which suggests a chicken-or-egg question. Language, intelligence and size of social group must have expanded together in humans. |
| 4932 | A conscious state endures for about 100 milliseconds, known as the 'specious present' [Edelman/Tononi] |
| Full Idea: The 'specious present' (William James), a rough estimate of the duration of a single conscious state, is of the order of 100 milliseconds, meaning that conscious states can change very rapidly. | |
| From: G Edelman / G Tononi (Consciousness: matter becomes imagination [2000], Ch.12) | |
| A reaction: A vital feature of our subjective experience of time. I wonder what the figure is for a fly? It suggests that conscious experience really is like a movie film, composed of tiny independent 'frames' of very short duration. |
| 23216 | The brain is not passive, and merely processing inputs; it is active, and intervenes in the world [Cobb] |
| Full Idea: A number of scientists are now realising that, by viewing the brain as a computer that passively responds ot inputs and processes data, we forget that it is an active organ, part of the body intervening in the world. | |
| From: Matthew Cobb (The Idea of the Brain [2020], Intro) | |
| A reaction: I like any idea which reminds us that nature is intrinsically active, and not merely passive. Laws are in nature, not imposed on it. My preferred ontology, based on powers as fundamental, applies to the brain, as well as to physics. No free will needed. |
| 23226 | There is a single mouse neuron which has 862 inputs and 626 outputs [Cobb] |
| Full Idea: Researchers have recently described a single inhibitory neuron in a region called the visual thalamus of the mouse - it has 862 input synapses and 626 output synapses. | |
| From: Matthew Cobb (The Idea of the Brain [2020], 11) | |
| A reaction: This is the kind of fact which philosophers of mind must be aware of when offering accounts of thought which are in danger of being simplistic. |
| 23513 | Single neurons can carry out complex functions [Seth] |
| Full Idea: It is increasingly apparent that even single neurons are capable of carrying out highly complex functions all by themselves. | |
| From: Anil Seth (Being You [2021], I.1 n) | |
| A reaction: Bang goes the simple connectionist account of consciousness. |
| 23514 | The cerbellum has a huge number of neurons, but little involvement in consciousness [Seth] |
| Full Idea: The cerebellum [at the back] has about four times as many neurons as the rest of the brain put together, but seems barely involved in consciousness. | |
| From: Anil Seth (Being You [2021], I.2) | |
| A reaction: I wonder if it also has four times as many connections? |