Learn English – ‘Eo ipso’ vs ‘Ipso facto’


Are these entirely interchangeable? Or is there sometimes reason to use one but not the other? (Other than, as one website says, to use 'eo ipso' rather than 'ipso facto' if you really want to be pretentious and obscure.)

Wiktionary says: 'eo ipso' = Through or by that very act or quality; thereby.
'ipso facto' = By that very fact itself.

I came across 'eo ipso' in this sentence:

It is one thing to say that I know what is good for X, while he
himself does not; and even to ignore his wishes for its – and his –
sake; and a very different one to say that he has eo ipso chosen it,
not indeed consciously, not as he seems in everyday life, but in his
role as a rational self which his empirical self may not know – the
'real' self which discerns the good, and cannot help choosing it once
it is revealed.

Best Answer

Ipso facto would not make sense in your example, as there is no 'fact' referred to. Eo ipso there means 'in or by himself', which does make sense with the qualification in the next clause.

Eo ipso is not a phrase to be recommended (unless you are writing abstruse philosophy, in which case you need a considerably greater command of the language than a website can help with); on the whole, I would avoid it praeter necessitatem.