The Tale of the Unknown Island by José Saramago

The fact that psychological time is not the same as mathematical time was something that Senhor José had learned in exactly the same way as, over a lifetime, he had acquired other types of useful knowledge, drawing first of all, of course, on his own experiences, for, despite never having risen higher than the post of clerk, he does not merely follow where others go, but drawing too on the formative influence of a few books and magazines of a scientific nature in which one can put one's trust or faith, depending on the feeling of the moment, and also, why not, a number of popular works of fiction of an introspective type, which also tackled the subject, though employing different methods and with an added dash of imagination.

However, on no other occasion had he had a real objective sense, as physical as a sudden muscular contraction, of the effective impossibility of measuring the time that we might call the time of the soul, as when, back in his house again, looking once more at the unknown woman's date of death, he struggled, vaguely, to place it in the time that had passed since he first set out to find her. To the question, What were you doing on that day, he could give an almost immediate response, he would just have to go and look at the calendar and, thinking simply as plain Senhor José, the Central Registry clerk who had been away from work sick, he would say, That day I was in bed with flu, I didn't go to work, but if they went on to ask him, Now relate it to your activities as a researcher and tell me when it was, then he would have to go and consult the notebook that he kept beneath the mattress, It was two days after I broke into the school, he would reply.