Subtle changes, bugs and feedback

And why a sans-serif font, when serifed fonts are naturally more readable.

Actually. not the case on the web.

Sans-serif constantly comes out top of readability tests on the web.

Perhaps when every device has 300dpi then it would be different, but for now... sans-serif wins on the web.

Serif continues to be king in print.

As the default, yes.

You're right on print... there's so much empirical evidence on that it's not even up for debate.

It is, of course, true that for most people serif fonts are easier to read, but there are exceptions depending on a person's individual requirements. For many dyslexic people, the less complexity, the better, and the best fonts to use for them tend to be sans serif fonts like Arial or Comic Sans, as they are very simple. Also, different people with different visual impairments require different font sizes. There is a wide range.

Does anyone want the text larger?

I'm (mildly) hyperlexic, so I prefer a smaller font. What was the previous default font, David? I'd quite like to retain that, as I've just been through the other fonts on my system and can't seem to find it--or perhaps I've just not tried that font with the right size setting.

You have to consider that if he knew what he was talking about and was really concerned about readability he wouldn't have set his article in a serif font.

The main scientific reason he is wrong is that we do not actually recognise and read words by looking at their letters. We recognise word shapes. We even recognise sentence shapes. Our brains store these shapes for future use and recall them instantly, enabling us to read much much faster than if we had to actually read the letters and construct each word they spelled. By increasing the font size to such a degree you have made it too big to do this easily, essentially reducing the number of words that we can scan in one go.

By making the letters bigger you therefore do not necessarily increase readability. Once the text is big enough to render the letters properly then it's probably big enough to read

Yes, although it depends on people's ability to engage with visual complexity. Most people would read in the way you describe. Severely dyslexic people, for instance, may not even recognise full word shapes, but only the beginning of words, which is why if you read a text they'd written, you might see something like 'the new caterpillar was estranged in open to ...' for 'the new category was established in order to ...' Hyperlexic people are the opposite in that they don't recognise word shapes, but individual letter shapes in high detail. They don't tend to need the simplification you describe for fast reading.