Question regarding typeface weight

[jugaadanimation]

Robert Bringhurst said in his book "The Elements of typographic style" that for a balanced page, the weight of the typeface should decrease slightly not increase, as the size of the text increases.

Then why it is that wherever I see, headings and subheadings are bolder than the body text?

If the headings are larger than the body text, why don't most people use a thinner typeface for headings?

Design principles state that there should be a hierarchy in a good design. Hierarchy can be achieved by using the bold typeface when they are of the same size, so that the eyes are attracted towards the bold text first. Why is then using bold typeface for headings considered bad?

[Ralf Herrmann]

3 hours ago, jugaadanimation said:

Robert Bringhurst said in his book "The Elements of typographic style" that for a balanced page, the weight of the typeface should decrease slightly not increase, as the size of the text increases.

Where exactly in the book does he say that?

But even without checking the context, I guess the key is the word “balanced”. If you want an even page, or even “color” as it is usually called, then what he says makes perfect sense. The larger the type, the thicker the stems and one could counter that with a thinner typeface. 

But that assumes that one actually wants to achieve an even color on the page. For some books that might be a perfectly valid choice, but its not a general rule covering every possible page design. 

 

Quote

Design principles state that there should be a hierarchy in a good design. Hierarchy can be achieved by using the bold typeface when they are of the same size, so that the eyes are attracted towards the bold text first. 

Absolutely. OR: You don’t change the weight at all, but only use a hierarchy of type sizes. And then you could try what Bringhurst suggests. Both options are perfectly valid.
(And there are of course more, like using color, style changes like italics, small caps and so on.)

[jugaadanimation]

20 minutes ago, Ralf Herrmann said:

Where exactly in the book does he say that?

Page 60, in the third chapter Harmony and Counterpoint.

30 minutes ago, Ralf Herrmann said:

But even without checking the context, I guess the key is the word “balanced”. If you want an even page, or even “color” as it is usually called, then what he says makes perfect sense. The larger the type, the thicker the stems and one could counter that with a thinner typeface. 

So it ultimately depends on the topic. There are multiple ways to achieve hierarchy and either way is right depending on the context. Thanks, this was really bugging me.