Are conversions to and from formats all or nothing?

[stevespages]

Firstly I apologize if this has been answered but I found it difficult to think of good search terms and I did not find an answer.

I am new to Pandoc and I am wondering if I have correctly understood the information on the home page (https://pandoc.org/) about conversions (from, to, from and to).

Just considering conversion to, it looks to me as if a given format can either be converted to by all other formats or by no other formats but I would have thought that some formats might be able to be converted to from a subset of other formats.

I suspect there is some logic about the situation which I completely missing and would be grateful to know if it is correct that a given format can either be converted to from all the other formats (listed on the home page) or by none of them. If this is true I would be interested in any explanation you think might help me to understand why.

I am now thinking that there is some intermediary format, say .pandoc, which can be coverted to by some but not all of the other formats and which can convert to some but not all of the other formats. Is that correct?

[badumont]

I am now thinking that there is some intermediary format, say `.pandoc`, which can be coverted to by some but not all of the other formats and which can convert to some but not all of the other formats. Is that correct?

That's it, it is explained at the beginning of the manual here: https://pandoc.org/MANUAL.html#description