I see that Peter Geach’s (1916 - dec. 2013 ) Mental Acts is available on internet archive:
Back in the dim and distant asking for it at the library desk where a few copies were on hold I was told that it would be kept in the Medical Library. Well I’ll be sectioned! Was there ever any more abstruse topic explicated with such clarity?
His observations on worshipping the wrong god (God and the Soul) seem to me to be unconvincing and the analogy from confusion of the personality and aims of some particular politician with another one and casting your vote on that basis doesn’t go on all fours. You may hold to a Triniatrian view of God and another to a singular Deity but to believe that prayers directed by a Jew or a Muslim go astray like a poorly addressed letter is not sensible. That is not his assertion but it seems a valid reductio.
God is the ultimate sorter. You may be going astray but you’re going astray in the right direction.