Rabbi Marc B. Shapiro writes: For parashat Metzora (p. 231), he quotes R. Kook’s statement in Ezrat Kohen, no. 21, that even if one expresses heretical thoughts, this doesn’t mean that he really is a heretic. Rather, it could be that he is simply trying to show that he is in line with what “the world” is saying, but it doesn’t mean that he really believes it.
This is just one more angle whereby R. Kook tries to defend the modern free-thinkers. His most famous defense is that modern heretics have the status of onsin [raised in captivity], in that the environment today almost forces them into their false beliefs so that they cannot be held responsible for their views. He also states that those who express heretical beliefs are not really certain of their heresy, and it is only one who is certain in this who is to be regarded as a heretic.
With the publication of Shemoneh Kevatzim we see that R. Kook goes even further and completely removes the orthoprax individual from the status of heretic…
We see from R. Kook that one who holds a heretical belief, but lives as an observant Jew in his daily life, is regarded as part of the Torah community. As I put it in my earlier post: Two important things stand out. First, while not condoning orthopraxy, R. Kook states that one who is observant, despite the fact that he denies ikkarim, is to be regarded as an erring Jew, not as a heretic. R. Kook’s position is a complete rejection of the idea that people who are shomrei Torah u-mitzvot can be read out of the fold and be regarded as heretics because of their incorrect beliefs. The second important point is that he rejects the Rambam’s entire theological conception of Principles of Faith and aligns himself with the Ra’avad, showing once again that the Rambam’s position has not attained unanimity.[29]