The author presents forgetting not as a failure of memory, but as a crucial function. The text states that the ability to forget is 'indispensable for keeping our mental activities sound' and that it prevents our brains from being 'flooded with trivial information.' It concludes by calling forgetting an 'important regulatory function.' This means forgetting helps filter out unimportant data to allow for clear judgment, which aligns with the idea that it's an indispensable brain function for selecting necessary information.