This is problematic though:
The sciences have come so far in the past hundred years that we can safely predict that the accelerating rate of knowledge accumulation within our intellectually
robust society will lead to the solution of this potentially very difficult problem by socially and morally acceptable means.
Accumulation is not permanent and loss of knowledge is possible (progress is never permanent and inevitable). If industrial civilization dies (and it will), then a lot of knowledge (especially complex knowledge that is energy intensive to initially produce and maintain such as say nuclear reactor technology) will be lost. Science is supported by state, military and business interests, so without them it collapses. Religious knowledge escapes this fate because it is ordinary people that generally maintain the knowledge traditions through thick and thin.
Anyway, I believe our mental faculties are diminishing. Not too long ago people would memorize vast amounts of literature (and this was not considered unusual or remarkable). Now it seems almost nobody can do this.
The other thing to take into account is that we live in a toxic environment. All the pollutants in our food, air and water no doubt have a detrimental effect on our body and minds.