- circumstanceThe debate about the merits of in the circumstances and under the circumstances continued for most of the 20c. The pedantic view is that since circumstances are, etymologically speaking, around (circum) us, we must be in them and not under them; but Fowler rightly rejected this argument as puerile and observed that under the circumstances ‘is neither illogical nor of recent invention (1665 in OED)’. The OED further noted that ‘mere situation is expressed by in the circumstances, action affected is performed under the circumstances’, a subtle distinction that is useful as a general guide but no more:
• Never, under any circumstances, solder connections to the tags with them already on the cartridge —Hi-Fi Sound, 1971
• As a writer, and collector of unusual information, I would be interested to hear from people who have seen the ‘little people’ or any strange, apparently non-human beings, under any circumstances whatever —Stornoway Gazette, 1973
• We understand that in normal circumstances we wouldn't be entitled to any money —radio transcript, AusE 2001 [OEC].Choice is also affected by the presence of an adjective or other qualifier for circumstances: in present circumstances, in exceptional circumstances, under these circumstances, under no circumstances, etc., are all idiomatic constructions.
Modern English usage. 2014.