Q: Presidents Brigham Young and Wilford Woodruff both taught that God is progressing in knowledge (Journal of Discourses 11:286, The Discourses of Wilford Woodruff, p.3). Yet President Joseph Fielding Smith said that “this kind of doctrine is very dangerous” (Doctrines of Salvation 1:8). Which prophet was telling the truth?
A: Although this webpage (http://www.lightplanet.com/mormons/response/qa/by_sermons_scripture.htm) doesn’t directly address your question, it addresses the underlying issue, which is that Mormons don’t believe that everything a prophet says is scripture (nor can we even be absolutely sure as to whether they’re being quoted accurately). As I’ve mentioned previously, we believe prophets have their own opinions, and those opinions may or may not be correct. Perhaps BT and WW were stating their opinions, and their opinions are wrong. Perhaps they were misquoted. Perhaps the word “knowledge” snuck into what WW was saying but he didn’t mean it to, a sort of speaking “typo”. Or perhaps when he used the word “knowledge” he didn’t mean it exactly the way we’re talking about it here. Whatever the case, if you got BY, WW, and JFS in the same room together to talk about the matter I’m sure they’d all agree.
My understanding of God is perhaps best summed up in this quote by Bruce R. McConkie “There are those who say that God is progressing in knowledge and is learning new truths. This is false—utterly, totally, and completely. There is not one sliver of truth in it…. God progresses in the sense that his kingdoms increase and his dominions multiply—not in the sense that he learns new truths and discovers new laws. God is not a student. He is not a laboratory technician. He is not postulating new theories on the basis of past experiences. He has indeed graduated to that state of exaltation that consists of knowing all things.”
Joseph Smith also taught that logically God must be omniscient otherwise it would be plausible that some other being might possess knowledge that God does not, and this knowledge could be used to thwart God’s plans. Such an idea would make exercising faith in God impossible and ruin everything.
So it seems to me that WW, when he used the word “knowledge” was either being misquoted, misspoke, or wasn’t thinking straight at the time. But it’s hard to judge with accuracy what somebody meant without being able to ask them. If we had him right here we could just ask him about all this and maybe he’d say “No, that’s not at all what I meant, what I meant was…”
But again, this is why it’s nice to have living prophets, because they can answer questions like this and clarify what the truth is.