Why aphantasia isn't something to be fixed
As someone with total aphantasia, I found Shayla Love’s article “Think of an apple” to be of great interest. I found out that other people could actually picture things in their minds only when talking to my wife some 10 years ago (11 April, p 36). She really struggled to believe that I can’t!
In particular, I found the section about two different visual processing streams extremely interesting. I hadn’t read of this before. It makes total sense because when I construct a concept of something in my mind, by putting together all the ideas that make up that “thing”, I find myself reaching in space and, in fact, placing those ideas in different spaces around my mind. I also feel that colours are strongly related to different positions in space. I can’t see them, but I feel where they are.
For this reason I’d be devastated to be able to picture things! I am certainly not going to try any “fixes”, because I feel strongly that it would crush my ability to think in the abstract, something I cherish.
How to think more positively about ageing
Regarding negative attitudes towards ageing, even though I have a heart health condition, I hardly ever think of myself as old. I’m 64, but even before I was 28, I always had that specific age in my mind, and so I routinely think of myself as being 28 years old (4 April, p 19).
I have other health issues 鈥� osteoarthritis in my knees, for example 鈥� but I just let them go. I think of them only when they show themselves. In my mind, such as it is (I have always had aphantasia), I am 28 and always will be.
We have far more than just five senses
In his interview, Michael Pollan says that plants have about 20 senses and “[w]e only have five or six”. That is a considerable underestimate. In addition to the traditional five senses, there are multiple senses falling under the general heading of “interoception”, including senses of heart rate, distension of various organs such as bladder and oesophagus, senses of hunger and thirst and gastric fullness, and bodily reactions that contribute to emotional sensations (4 April, p 26).
There is also the proprioceptive system, a term that covers multiple senses concerned with body movement and posture, balance, muscle force, muscle fatigue and a sense of heaviness of lifted objects. Whatever consciousness might be, you have no hope of understanding it if you neglect most of the sensory systems that feed into it.
Investigating how smaller tools led to bigger brains
The suggestion that switching from large to smaller prey drove the increase in brain size of early humans raises an obvious question. How did smaller-brained humans with the stone tools described manage to kill “massive plant-eating prey”? An animal is hardly likely to stand still and wait to be axed or clubbed to death at close quarters (18 April, p 10). The tools were suitable for butchering, but surely the early humans were scavenging, not killing large prey?
Another view on how we experience time
Referring to mentions of time in recent editions of 麻豆传媒, I would like to offer an opinion. The spatial dimensions of north, south, east and west define an object in instant space but, as virtually all matter is in constant relative motion, there is a need to measure change between events caused by this motion 鈥� we call this time. But this time dimension doesn’t complete our picture, as nearly all matter deteriorates through lack of stability 鈥� its entropy changes (Letters, 7 March).
I don’t perceive time as flowing, but that time measures the difference between events. Those events are affected by entropy, and we see that change from one event to another, and as in film, one frame at a time flows into apparent motion. Therefore, time flow is an illusion. Time doesn’t begin or end; it is just another space between events. It is the change in entropy that we experience.
Going along where the wind blows
Stone Age seafarers had a good understanding of local conditions, wind directions and the local geography, without having the use of compasses. I would suggest that although it would have been difficult to find Malta from Italy, it would have been much easier to find Italy from Malta. It required only one sailor with sufficient skill who found themselves blown towards Malta to wait until the wind was in the opposite direction, then make their way home again (Letters, 14 March).
Their family and friends had to wait only until the conditions were the same as on their first trip to repeat the journey.
Life and the cosmos are less separable than ever
It is not surprising that the asteroid Ryugu, among others, possesses the nucleobases that are core components of nucleic acids. I am reminded that the Murchison meteorite, impacting Australia in 1969, was replete with organic compounds, including a cache of amino acids and some nucleobases also found in terrestrial life (28 March, p 15).
Did such abiotic nitrogenous bases and amino acids seed the early warm, incubating Earth as a prelude to their syntheses into nucleic acids and proteins? These observations complement the 1952 experiments of Urey and Miller that used electrical sparks (as simulated lightning) to form a mixture of amino acids from reduced gases associated with the primordial Earth. Life and the greater cosmos surely are less separable than ever.
A word of warning from a retired school teacher
With a number of jurisdictions proposing social media bans on young people, may a retired secondary school principal offer a comment? Don’t announce a regulation until an effective means of enforcement is in place. Most importantly, never underestimate the ingenuity of teenagers (Letters, 11 April).
For the record
The children pictured are playing chess (25 April, p 32)