The original discussion was seven years before the term aphantasia was introduced in 2015. There is a spectrum from aphantasia, where someone can't see images in their mind, to hyperphantasia, where imaginations are as vivid as seeing.

So this thread quickly shed light on some of this variation, before modern framing of these differences. This was a missed opportunity to spread this knowledge earlier. I didn't find out that I'm basically aphantasiac until 2023 from a Facebook meme. 

Even though I don't have a visual imagination that I can control, I know my body can do it. One of the 15 side effects and consequences of being hurt by the antibiotic Ciprofloxacin was a couple of weeks of seeing images when I closed my eyes. For someone who is not used to that, it was scary. The images seemed to be memories.  

So, there may be some layers to this with how the brain functions and variations of subjective experience, on top of that.