You may want to check your facts on Facebook.
1. For images, use Google in image search mode to find out whether the image is what the post claims it is. Write google.com, click “images”, click the camera icon and either upload an image or paste the url. To save your image so you can upload it, right-click the image to get a popup menu and choose “save picture”. The image usually lands in “downloads”.
2. For blogs and web-newspapers. Check the source of the post. Look it up in wikipedia.org. If it is not listed, then it is not a reliable source, and probably just a blog. If found, read what Wikipedia says about it. The best newspaper sources are those that have hundreds of full time fact checkers employed like Der Spiegel, The Guardian and The New Yorker. Most local newspapers do not have a single one employed.
4. For quotes, check wikiquote.org. I have found no other good sources.
5. For texts, just google relevant words from the new story and add the word “Hoax”. See if any source google finds is a realiable hoast. You can also check in snopes.com.
In Theaetetus, Socrates develops an account of what knowledge is which goes something like this. You have knowledge when you believe in something, that something is true and you have a justification for believing it. This is the classic account of what it means to know something.
I have a simpler description which fits better with how we think we know things today. You have knowledge when you believe in something and that something happens to be true.
I consider the addition of justification akin to a “no true Scotsman” fallacy.
Here is an example of a “no true Scotsman” fallacy.
Person A: “No Scotsman puts sugar on his porridge.”
Person B: “But my uncle Angus likes sugar with his porridge.”
Person A: “Ah yes, but no true Scotsman puts sugar on his porridge.”
To claim that my simple definition is “not true knowledge” follows the same pattern. A good justification will improve the credibility of the knowledge, but even without any justification, it is still knowledge.
Person A: “No one can know a fact without justification.”
Person B: “But my uncle Angus is Scottish and he knows that he is Scottish and says he just knows it without any justification .”
Person A: “Ah yes, but if it had been true knowledge, he would have a justification for it.”
I originally stated this 2012-12-10 in a philosophy discussion hosted by Coursera for the department of philosophy at EdinburghUniversity.