I don’t know, i disagree with him, but i do not know that it is invincible ignorance. I think he is suggesting that Christ is the only way to God. Those of other religions, being ignorant, do not know they are pursuing Christ, but they are chasing the “light” by which their heart may be illuminated by Christ, though they may not have explicit knowledge that it is Christ. They have accepted Christ without explicit knowledge of doing so. That’s how i understand it. I disagree, but it is a fascinating position (i think i have portrayed it accurately). If nothing else it proposes a solution to this dilemma, even if it be a false one.
You have given a very nice description here.
In parallels very nicely the Church’s position as expressed in the Catechism;
847 This affirmation is not aimed at those who, through no fault of their own, do not know Christ and his Church:
Those who, through no fault of their own, do not know the Gospel of Christ or his Church, but who nevertheless seek God with a sincere heart, and, moved by grace, try in their actions to do his will as they know it through the dictates of their conscience - those too may achieve eternal salvation.
This then is the “official” description of how this can occur.
Now what I like particularly about your description above is your reference to, “the “light” by which their heart may be illuminated by Christ”, for in order to know if the person is on the “right track” we need to know what that “light” is and to know that we need to know what is the light that Christ brought into the world…Not the name(s) but the essences.
What Scripture points very clearly to is that Agape Love is that light. There are many examples, both explicit and implicit that bear this out. Perhaps the most explicit is this one.
1John 4:7-8
7 Beloved, let us love one another; for love is of God, and he who loves is born of God and knows God. 8 He who does not love does not know God; for God is love.
“He who loves is born of God and knows God…for God is Love.” How powerful a statement and how inclusive. Like the Judgement passage in Mt 25:31-46, this passage is about who the person is in their core being - a child of light (love) or a child of darkness (hate).
In the Gospels, Jesus tells us that it is Love that underpins all of the law and prophets (Mt 22:36-40)…He also tells the disciples that the world will know that they are His disciples by their Love (John 13:34-35)…and then of course we have St Paul’s incredibly beautiful exposition on the absolutely foundational necessity of Love contained in 1 Corinthians 13:1-13.
So - the “light” that you refer to above…if it is of God…will be love…Agape…Selflessness.
And if we see that light in one not of the Christian faith, how can we deny that such a one is a disciple of Christ - even without their knowledge? Likewise when we see
no light coming from one who claims discipleship, should we not be reminded of Jesus own words that "not all who cry Lord Lord will enter the Kingdom, but rather those who
do the will of my Father. (Mt 7:21) And the Father is Love so Love is His Will.
That is my take on the subject anyway.
Peace
James