When do we use this phrase "can't but verb"? (I can't but disagree.)

Hello everybody!
I really need your help!
Can I say: “Personally, I CAN’T BUT DISAGREE with those who say…”, with the meaning of " I can’t do anything but disagree…" ?
Is it correct and can I use this expression in written language?
Thanks so much in advance!

Hi Claudia,

An interesting question. Let me try to offer a suggestion. I think what you need is an additional word in this sentence so that it reads: I can’t help but+infinitive. A couple of examples: I can’t help but feel sorry for them although it’s their own fault. The meaning behind this is that you can’t stop yourself feeling sorry for them although you know they did something stupid. Again: I can’t help but admire people when they join protest marches in the street. Here the meaning is that in a way you can’t stop admiring them although you wouldn’t do it yourself. You will notice that both ‘infinitives’ (feel and admire) are positive and I think that if you use a negative verb in this construction, then there is a danger of creating a ‘double negative’, which confuses the meaning. Back to your sentence: I can’t but disagree or to add ‘help’ I can’t help but disagree - the meaning is not clear because ‘disagree’ has a negative sense. You could adapt the sentence to read: I can’t help but think you are wrong’ or ‘I can’t help but express/show my disagreement …’.

I hope this helps.

Best wishes