But exceedingly fine.
This distinction between significant and insignificant heresy is not immediately obvious, since a person who adopts what will turn out to be a fatal heresy retains much from their previous state, and their behaviour may not change much immediately – the implications of a heresy will typically become clearly apparent only across the timespan of one or two generations.
Thus Bruce Charlton.
Brother Holland gave a controversial talk some years ago in which he warned that children would often pay the price for their parents’ apostasy:
I speak carefully and lovingly to any of the adults of the Church, parents or otherwise, who may be given to cynicism or skepticism, who in matters of whole-souled devotion always seem to hang back a little, who at the Church’s doctrinal campsite always like to pitch their tents out on the periphery of religious faith. To all such—whom we do love and wish were more comfortable camping nearer to us—I say, please be aware that the full price to be paid for such a stance does not always come due in your lifetime. No, sadly, some elements of this can be a kind of profligate national debt, with payments coming out of your children’s and grandchildren’s pockets in far more expensive ways than you ever intended it to be.
All my experience since has taught me that he was right. Parental teaching is a strong shove down the river of life from which even the most frantic paddling may not suffice to reach the safety of another channel before going over the falls. The falls grow deeper every year.