As he also noted, structures of sin "grow stronger, spread, and become the source of other sins, and so influence people's behavior." ( Sollicitudo Rei Socialis, 38)"such cases of social sin are the result of the accumulation and concentration of many personal sins. It is a case of the very personal sins of those who cause or support evil or who exploit it; of those who are in a position to avoid, eliminate or at least limit certain social evils but who fail to do so out of laziness, fear or the conspiracy of silence, through secret complicity or indifference; of those who take refuge in the supposed impossibility of changing the world, and also of those who sidestep the effort and sacrifice required, producing specious reasons of a higher order. The real responsibility, then, lies with individuals." (Reconciliatio et Paenitentia, 16)