[MUSIC] ENGLISH for TEACHING PURPOSES. Expressing CERTAINTY. >> Sometimes we say, dubious stuff in class. [MUSIC] And when we do it. We use language, to reflect where we stand. [MUSIC] On this video we'll talk about the expression of certainty, as something that has to do with personal or scientific stance. After all, if you're personally invested in a particular finding, you will tend to present it in ways that suggests such findings truer, than any competing theories. Certainty also relies on more superficial viewpoint aspects. And it is unquestionably related to the emotional links, we look around our messages. Halliday and other linguists, believe that the expression of certainty is an essential layer of meaning. That basically means, that the degree to which we believe in anything we say is always encoded in the actual message, whether we chose to put it out there or not. Certainty is quite evidently a matter of degrees. And it tends to live in the realm of verbs and their accompanying adverbs, though it can also be expressed by other means. This is how it goes. Let's say that when we express something using the present simple, positive or negative. We are indeed saying, we're absolutely sure that. That's the highest degree of certainty. But when we use a model form like might, we are expressing without a shadow of a doubt, that we feel more than dubious about the truth of our message. As I said earlier, when you use a present simple, you're engraving the highest degree of certainty onto the sentence. It is the tense of facts, as in the Earth is round, all humans are born equal, or plastic isn't an organic product. Sometimes we can also use a future form, to express complete certainty. The minute hand will move clockwise every minute. A high degree of certainty can also be expressed by means of the negative form of can. When we use it, we're denying the possibility for something to happen. Check this out. Anvils cannot float. Go ask Miley Culorey, once we cross this line, we leave the realm of certain, and we enter the world of only possible. So you are pretty sure something is true, but can't really swear by it. In that case, you will probably need to use must. You see, must says yes, I believe this is true, but I still can't claim it is. The patient's lack of response must be due to her condition, but we need to run more tests to be sure. It all goes downhill from here. Let's use the same example, and see how it varies in meaning. The patient's lack of response can be due to her condition, but we don't know for sure. Or, the patient's lack of response, could be due to her condition, but we need to run more tests to be sure. The previous sentences express that the patients condition is a cause, as possible as any other for the patients irresponsiveness. Let's say that there is no more than 50% certainty, that the condition is to blame. Following can and could, we find may and might, which encode doubt rather than certainty. Let's see what the previous example would look like, when using may and might. The patient's lack of response may be due to her condition, but we need to run more tests to be sure. And the patient's lack of response might be due to her condition, but we need to run more tests to be sure. The level of certainty expressed by both these modal verbs is very low. So low, that we tend to use either one of these expressions when we're making a less than educated guess. People rarely make a difference between may and might, but I think there is a real difference, though slight. Bear that in mind if you want to emphasize that tiny little possibility that goes up or down. The most efficient way to express certainty, is by relying on the use of tenses and modals. However, adverbs add an interesting layer of meaning, by helping us establish how predictable something is. For example, it is slightly different to say water boils at 100 degrees celsius, than saying water always boils at 100 degrees celsius. Especially because we all know that, only under certain circumstances does water boil at exactly 100 degrees celsius. What I have added to the latter sentence is an adverbial, only under certain circumstances. And an adverb, exactly. Which help establish the conditions for the sentence to express something that is true, and for the speaker, in this case, me, to feel certain about it. You see, by adding information about when, why, or how something happens, we draw a sort of line between the things we believe to be true. And the ones that are, less true for ourselves. Always bear in mind that the certainty you print onto your statements, is nobody else's but your own. This means that being aware of the workings of the expression of certainty is actually important. I really believe this is all we got for you today. See you next time I guess. [MUSIC]