'Which qualities are commonly thought to be the same in those bodies that those ideas are in us'

Question

_{Source: p 210 Bottom, Introducing Philosophy for Canadians: A Text with Integrated Readings (2011 1 ed).
Primary Source: Book 2, Chapter 8, ¶ 16, An Essay Concerning Human Understanding (1689) by John Locke.}

16. Examples. Flame is denominated hot and light; snow, white and cold; and manna, white and sweet, from the ideas they produce in us. Which qualities are commonly thought to be the same in those bodies that those ideas are in us, the one the perfect resemblance of the other, as they are in a mirror, and it would by most men be judged very extravagant if one should say otherwise. [...]

_{[ 2007 Paraphrase by Jonathan Bennett :]} 16. Flame is called ‘hot’ and ‘light’; snow ‘white’ and ‘cold’; and manna ‘white’ and ‘sweet’—all from the ideas they produce in us. [We know that Locke sometimes calls qualities ‘ideas’, but that seems not to be enough to explain the oddity of the next sentence down to its first comma. The passage as given here is almost verbatim Locke; all of the oddity is there in what he wrote.] Those qualities are commonly thought to be the same in those bodies as those ideas are in us, the one perfectly resembling the other; and most people would think it weird to deny this. [...]

I do not understand the sentence coloured in grey. Please correct my conjectures:

1. 'Qualities' refers to 'hot and light', 'white and cold', and 'white and sweet'. Correct?

2. Are 'flame', 'snow', and 'manna' the bodies?

3. Then what are the Ideas in these 3 examples?

4. What sameness is the sentence trying to communicate? Both Locke and the Paraphrase appeared to have performed a Gapping Ellipsis that I complete:

Those qualities are commonly thought to be the same in those bodies as those ideas are [commonly thought to be the same] in us

Answer 1

Qualities such as hot, light, white, cold, etc. are phenomena that objects produce in us. However, the average person isn't aware of that, so they usually attributes those qualities to the objects themselves. Physiologically that's impossible, because we simply don't have direct access to the objects themselves. There's a neurologically chain of events that takes place in order to carry signals from the outer world to the brain. The following is from a psychology text:

"The brain never receives stimulation directly from the outside world. Its experience of a tomato is not the same as the tomato itself—although we usually assume that the two are identical. Neither can the brain receive light from a sunset, reach out and touch velvet, or inhale the fragrance of a rose. It must always rely on secondhand information from the go-between sensory system, which delivers only a coded neural message, out of which the brain must create its own experience." (Psychology Core Concepts, p. 90)

Thus, when Locke speaks of qualities "commonly thought to be the same in those bodies," he is talking about how the common man often attributes how things seem to us (the phenomena) to the things in themselves. For example, the sensation of cold belongs to our perceptual faculties, i.e. neural signals carried to the brain and the particular manner in which the mind interprets those signals as conscious experience. Those sensations should be distinguished from the causes. In the case of snow, we can attributed the cause to the low thermal content of the ice particles. The sensations belong to us, and the energy content to the snow. The same can be said for our other senses, such as the perception of color. The phenomenal experience of white should be distinguished from the electromagnetic energy that stimulated the photoreceptors in our eyes. The sensation of color belongs to us, and the energy belongs to the light rays that enter the eyes.

It should be noted that Locke used the names of colors when referring to phenomenal qualities, i.e. to the ideas in the mind. However other philosophers have strongly objected to using language in this way. Thomas Reid, for example, criticized the "the way of ideas" for this very thing. Reid also recognized that phenomenal experience should be distinguished from the things in themselves, but he objected to calling the phenomenal experience of a red object as "red." Instead, he insisted that the name of the color belongs to the object and not to the phenomena.