`Abdu'l-Bahá is known by Bahá'ís to have been infallible, but Bahá'ís don't all agree on the extent of that infallibility.
This issue has arisen in the wake of growing awareness that some things `Abdu'l-Bahá said about science, history, and the future may have been incorrect. Some Bahá'ís, tending to be more scholarly, attempt to alleviate this problem by explaining that `Abdu'l-Bahá was infallible with regard to doctrine, but not with regard to the world. Other Bahá'ís find this to be a dangerous compramise that makes `Abdu'l-Bahá's writings as a whole more difficult to interpret.
To address this issue from a Bahá'í perspective, let us consult the Bahá'í writings. First, let's look at what Baha'u'llah said.
In the Surah of the Branch, Baha'u'llah, speaking with the voice of God, makes `Abdu'l-Bahá's greatness unquestionable to Baha'is:
... for verily He is the most great Favor unto you, the most perfect bounty upon you; and through Him every mouldering bone is quickened. Whoso turneth towards Him hath turned towards God, and whoso turneth away from Him hath turned away from My beauty, hath repudiated My Proof, and transgressed against Me.
Lofty praise indeed. The infallibility seems to be implicit in Bahá'u'lláh's directive to Baha'is that they accept `Abdu'l-Bahá unhesitatingly as their leader and the authorized interpreter of Bahá'u'lláh's writings. Clearly, Bahá'u'lláh does not declare that `Abdu'l-Bahá is infallible in matters of science, only that Bahá'ís should follow him and his interpretation of scripture. This doesn't mean for certain that Bahá'u'lláh didn't grant unrestricted infallibility to `Abdu'l-Bahá, but he sure wasn't very clear about it.
As to what `Abdu'l-Bahá said that Bahá'u'lláh said about him (as he roughly paraphrases the Kitab-i-'ahdi):
All must turn to Him. Whatsoever He says is correct, for, verily, He knoweth the texts of My Book. Other than He, no one doth know My Book.
The Promulgation of Universal Peace, pp. 322-323
Although this passage says that "Whatsoever He says is correct," he is obviously speaking in terms of scriptural interpretation, though some may interpret the term My Book as meaning the book of general revelation, that is, of nature.
As we look through the further passages in Promulgation of Universal Peace, we see that `Abdu'l-Bahá continually refers to his station as an interpreter, not necessarily as an unrestricted source of perfect knowledge.
"I am," He, in this same connection, affirms, "according to the explicit texts of the
Kitab-i-Aqdas and the Kitab-i-'Ahd the manifest Interpreter of the Word of God . . . Whoso deviates from my interpretation is a victim of his own fancy."
`Abdu'l-Baha, quoted in The World Order of Baha'u'llah, p. 138
But we do have this from Baha'i World Faith:
... the Blessed Beauty (may my soul be a sacrifice unto Him), has through the Supreme Pen written the Covenant and the Testament; He appointed a Center, the Exponent of the Book and the annuller of disputes. Whatever is written or said by Him is conformable to the truth and under the protection of the Blessed Beauty. He is infallible.
Baha'i World Faith, p. 358
This passage appears to close the case. It's much more explicit and unequivical than anything else I'm aware of. Of course, it's not an authoritative translation, but then neither is "Promulgation of Universal Peace". Still, this passage may exist with a similar meaning in a later publication. Anyone have any idea? I'm willing to accept that it is authoritative Baha'i doctrine that `Abdu'l-Bahá is infallible in all matters (notwithstanding any conflicts with current science), but I am not yet convinced by these references to scripture.
What is compelling to me is that `Abdu'l-Bahá was perfectly confident about everything he said, as though he believed that he was infallible. Since his infallibility with respect to guidance cannot be questioned by Bahá'ís, it seems clear that he was implying that he was infallible in all respects.
Now, as for what Shoghi Effendi said on the matter, no discussion is necessary, as Shoghi Effendi appeared to be a true believer in `Abdu'l-Bahá's unrestricted infallibility. Shoghi Effendi defended `Abdu'l-Bahá's every word, even `Abdu'l-Bahá's statements about science, history, and the future. The Guardian had no doubt that `Abdu'l-Bahá was infallible regarding worldly matters. For example:
Historians cannot be sure Socrates did not visit the Holy Land. But believing as we do that `Abdu'l-Bahá had an intuitive knowledge quite different from our own, we accept His authority on this matter....
Shoghi Effendi, Arohanui (1946)
Therefore, Bahá'ís must regard `Abdu'l-Bahá's statements about science, history, and the future as fact.