A.'s reflections on the phenomena involved in excuses are preceded by a plea for the kind of investigation he is undertaking (in which the main points are: we might reach a better understanding of what 'doing an action' means by studying cases in which there has been some abnormality or failure, which the word 'excuse' indicates; and since words are tools that have served people for ages, concentrating on 'ordinary language' will probably teach us more than abstract thinking).