Samuelson correctly notes that if people discount the future at rates that vary over time, then people may not behave consistently, that is, they may change their minds as time moves forward. The specific case he worries about is the same one that worried earlier economists such as Jevons and Pigou, namely, the case where we are most impatient for immediate rewards.
we could encourage retirement payment via showing them what they lost for not increasing the payment
