What had begun as a system of large-scale insurance had simply become a system of taxation, with today's contributions being used to pay today's benefits, rather than to accumulate a fund for future use. This 'pay-as-you-go' approach had replaced the principle of thrift with the practice of entitlement . . . [But this approach] is rooted in a false conception of how human beings behave. It destroys, at the individual level, the link between contributions and benefits. In other words, between effort and reward.