To be PERFECTLY honest with you I would have to find it myself but I DO know he advocated, that in order for one to be PROPERLY educated, one's mind must be first freed of such petty (to him) distractions as family and faith.
I will attempt to find more direct citations when I find time.
Well...if one wants to devote the whole of one's being to education--i.e., plumbing the depths and scaling the heights of the greatest questions asked by the greatest minds of the human race, must one not be willing to give up one's family to have the time to do so and be willing to question the dogmas of particular revelations?