Acne, young or old, we can all have different experiences with it. There are a lot of claims or hacks on the Internet to get rid of pimples fast. If you live through the '90s, you might remember putting toothpaste on them overnight, it was popular, which can actually also be irritating. Nowadays, jade rollers and charcoal are circling the internet to detox your skin. With all those tips and tricks out there, how do you evaluate them? To think critically about claims, means we cannot always accept that the explanation provided to us is the most correct. We need to think analytically and consider alternative explanations. In this video, we will learn how to consider alternative explanations by creating and ruling out rival hypotheses, because we cannot assume that only one explanation exists, but alternative explanations need to be based off systematic evidence. Let's consider, for example, a common claim, an explanation. If you are experiencing a bad breakout, be sure that you're washing your face and stop eating greasy foods. Now, this claim may very well be correct. But what are some ways we can be more confident in this explanation? We can create an alternative explanation which functions as a rival hypothesis. Like acne can be caused by factors other than poor hygiene and poor diet. It can also be caused by changes in hormones, from genetic predispositions, stress, or even puberty. Now that we have a rival hypothesis, we need to evaluate the evidence available. When we do a simple evaluation of the evidence, we can see that there is a lot of casually collected anecdotal evidence or personal testimony, and some evidence that has been systematically collected in an unbiased manner. Within the anecdotal evidence, we see a consensus among those who have had breakouts, that being in greasy places and certain face washes made their acne worse. Given that with anecdotal evidence, there is a high risk of bias in the personal report, let's look at any attempts to scientifically evaluate this claim. It appears there are many peer-reviewed studies currently available to help provide evidence to help us evaluate our rival hypothesis. From reviewing the details of this study, it appears that facial skin cells are responsive to stress hormones. This, among other studies, provide evidence to support our rival hypothesis. However, upon further research, there is still also ample evidence to suggest that acne can occur outside of hormonal changes, due to diet or exposure to certain bacteria on the skin. This is an example of why we cannot just accept any explanation provided to us, even if it comes from an expert. Critical thinking skills are important at the social level, they're important at the individual level, and I think it's something that we should all try to deploy throughout our whole life. We need to take an active role and consider the evidence available as well as the source of the evidence available. If evidence is not systematically collected, it is low quality and should be disregarded in building explanations. That being said, low-quality evidence, like anecdotes, or expert opinions, or even pseudoscientific claims, are still useful for providing us, critical thinkers, the opportunity to generate testable rival hypotheses. Generating rival hypotheses allow us to follow the scientific method and systematically collect and evaluate evidence to better inform our general explanations. When faced with a claim, acknowledge that alternative explanations or rival hypotheses may exist. We can then think critically by evaluating the available evidence and the source of that evidence to rule out rival hypotheses. If evidence available cannot rule out rival hypotheses, it is worth considering that alternative explanations may exist, and that the current explanation is from a scientific standpoint, not conclusive, and deserves reconsideration.