One of the questions I often get is what to do when you don’t have any evidence ready and whether it makes sense to make some evidence up in that case. Well, let me be honest, in a lot of cases you can get away with making up evidence as long as it is about an obscure subject that not a lot of people know about. So if you give a made up example of the political outlook of the Ogoni tribe in Nigeria then chances are people will believe it, why wouldn’t they? Especially if it matches perfectly with your EXplanation.
The same is the case with statistics. You can easily make up a statistic, or manipulate statistics so that they give the result you want. That’s really not that difficult. This has however led to many people being quite skeptical about statistics and obscure evidence. The reason being that they cannot check the validity, or relate it to anything they do know.
This also brings us to the danger of providing false evidence. If you use it there is always a chance someone in your audience will know it’s not true and even if they can’t then you also run the risk of someone Googling it at home. The result is that you might win that particular debate, or not even that if you are really unlucky, but that afterwards you are found out and your reputation is shot to pieces. This could have serious consequences for your Ethos and subsequently your ability to convince people in next debates. Why would people ever trust your evidence again? Although truth be told, enough politicians even seem to get away with that.
But what does this teach us on how to present your evidence? Suppose you provide evidence to support your argument, but the opposition claims it is false or incorrect evidence and puts forward some other evidence. How will your audience be able to decide which evidence is in fact correct? The clue lies in the fact that it is so easy to lie with evidence. As a result of that your audience wants to get the feeling they can check whether it is true or not. In order to appeal to that desire you can do two things. First always provide details. It’s more difficult to lie with details, as they have a tendency to get mixed up. So when you provide a lot of details, it gives the impression you really know what you are talking about and thus it must be true. Secondly details give more opportunities to check whether it is true, even if that is after the debate. So by providing more details than your opponent, you could tip the balance towards your piece of evidence. However, providing more details costs time and could make your argument more complex. This could actually reduce the overall persuasiveness of your case, so keep that in mind.
So what to do when you don’t have any evidence? My advice would be not to make up evidence, but to focus more on the EXplanation. Make sure your EXplanation seems sensible to your audience by making sure it’s clear, logical and understandable, but most importantly appeals to mechanics, assumptions, lines of reasoning your audience already believes or finds plausible. The purpose of evidence is on the one hand to support your premises and on the other hand to make your EXplanation more tangible by providing an illustration. If you use premises that your audience find plausible and present them in such a way that they are as tangible as possible, then you can very well get away with providing any form of evidence. Your audience will subconsciously provide the evidence themselves.