Yesterday and the day before, we discussed the halacha (Jewish law), the Gemara, that is a safek (doubt). The Gemara is saying that if you said the correct beracha (blessing) but with the wrong intent, it's a safek. So if, for example, you said, “Shehakol nihyeh bidvaro” (That everything came to be through His word) on water, fine, but you thought it was wine, so you thought you were going to say—and then at the last minute you change back to “Shehakol nihyeh bidvaro,” the Rif says we don't repeat the beracha; we do the kula (leniency), the safek, because it's a safek, and you have a problem of saying the shem Hashem (Name of Hashem). Perhaps you don't have to say it, so therefore we don't repeat the beracha. So we call that yatza (fulfilled), bediavad (after the fact), yatza.
So let's go from here, to a little bit deeper. Now, what happens if my safek happens with birkat ha-mazon (Grace after meals)? So I say, “Baruch Ata Hashem” (Blessed are You, Hashem). I'm thinking Asher Yatzar (Who formed); you're in the bathroom, thinking Asher Yatzar, and then, according to the Rif, it's safek de'oraita (Torah-level) now, not safek de'rabbanan (rabbinic). What would you say regarding birkat ha-mazon? Does it work or doesn't it work? You would say no. Hacham Ovadia says it works. Why? It's complex, but I'm going to try. For that, we have to go back to the Rambam.
The Rambam says that if somebody has to say birkat ha-mazon and has a safek about whether he said birkat ha-mazon or not, he has to say birkat ha-mazon, safek de'oraita lechumra (stringently). The Mefarshim (commentators) ask a question: You have a safek de'oraita on both sides, because if you already said birkat ha-mazon, he's going to be saying beracha levatala (blessing in vain), so you have a safek de'oraita to say it, and you have a safek de'oraita not to say it. Why do you favor saying safek de'oraita lechumra to say it? Same safek, but backwards. If you already said it, you're going to say beracha levatala; that's also de'oraita. So why do you say to say it? Over there, the Acharonim (later authorities) say, well, because there's a chazakah. What's the chazakah? Since you ate but you don't remember if you said birkat ha-mazon or not, therefore you have a safek shakul (evenly balanced), safek, safek, and you have a chazakah because you are full. You have a chazakah. The chazakah is going to tilt the safekot (doubts) to the side of saying it.
Hacham Ovadia says that in our case, you don't have that chazakah, because you said the birkat ha-mazon. It's not that you don't know whether you said the birkat ha-mazon, but you ate. “Ah, you ate and you don't know, therefore say it.” “No, no, you said the birkat ha-mazon.” The chazakah of eating is not going to tilt your safek to one side or another, because that's already done. That was for saying birkat ha-mazon. You said birkat ha-mazon. The safek is, does birkat ha-mazon like this work or not? It's a pure safek. “Ah, pure safek? So you have a safek de'oraita shakul on both sides?” “If you have a safek de'oraita shakul on both sides, why should you favor the safek de'oraita of saying it over the safek de'oraita not to say it? Maybe it's beracha levatala. Therefore, shev ve'al ta'aseh adif (refraining from action is preferable): you don't repeat birkat ha-mazon.”
The thing is, it's not because it says you don't repeat birkat ha-mazon yatsar; we don't know. We don't know what to do, and therefore don't say it. That's why a person should be very careful with the kavanah (intent) and the berachot (blessings). From the beginning, you think: What beracha am I going to say? If you're going to say Asher Yatzar, say Asher Yatzar from A to Z. If you're going to say birkat ha-mazon, start well, but switching in the middle like this brings huge safekot. And because we're saying halacha lemaaseh (practical halacha), you don't repeat. It could be that the person who is not yatsar, safek, we don't repeat. And therefore, that would be a beracha, but of course a person has to think and have kavanah; that way, he doesn't get into these safekot and berachot.