자료 1: http://english.stackexchange.com/questions/88332/meaning-of-schemas-are-changed-infrequently-if-at-all
자료 2: https://www.englishforums.com/English/IfAtAllUsage/hqcvr/post.htm
※ 발췌 (excerpt):
The basic structure is <A1, if not A2>, where A2 is an adjective or adverb in the same scale as A1, but more extreme. For example:
- reddish, if not red
- most, if not all
- some, if not most
- sometimes, if not often
if A2 is a negative, however, the double negative <not A2> looks odd or ungrammatical, and is rewritten as a positive.
- few, if *not none → few, if any
- rarely, if *not never → rarely, if ever
Your example [in the source link 1] is one of these rewritten double negatives:
- infrequently, if *not not at all → infrequently, if at all
The sense in all these is "I assert A1, but I will not go quite so far as to assert A2, although I hold it open as a possibility."
※ 발췌 (excerpt):
"if at all" occurs after expressions of scarcity, smallness, and the like─words like ^little^, ^few^, ^slow^, ^barely^, ^hardly^. And it reduces that small amount of something to zero.
- More women are having ^fewer^ children, if at all.
= More women are having ^fewer^ children, if they are having ^any^ children at all.
= More women are having fewer children, or they are not having ^any^ children.
- Use alcohol in moderation, if at all.
= Use alcohol in moderation, if you use ^any^ alcohol at all
= Use alcohol in moderation, or don't use any alcohol.
^If at all^ also occurs in questions.
- When, ^if at all^ will the economic recession end?
= ^When^ will the economic recession end, if it does end ^at any time^?
- How will blogging affect the practice of law, if at all?
= ^How^ will blogging affect the practice of law, if it has ^any^ effect at all?
- In what way, if at all, does global warming affect you?
= ^In what way^ does global warming affect you, if it affects you ^in any way^ at all?