To support a thesis, it is necessary to collect what in ancient times were called "proofs", that is, basically, facts and data. Facts and data do not require any special oratory skill to be shaped, they only need to be found, collected, selected, and placed at the right moment of the speech. Facts and data are very important: when they are introduced in a discussion, they are like “big stones” that cannot just be ignored. There are several ways to respond to an interlocutor who presents us with facts. First of all, you can dispute the fact: "This false! This is not correct!”. This equals to throwing away the stone. As an alternative, you can challenge the relevance of the facts: "Ok, this may be true, but it is not relevant to the point we are making, for this reason ...". This equals to acknowledging the stone, but bypassing it. As another alternative, you can dispute that the data and facts are partial and therefore not reliable: "You are only showing data on this point, but if you check these other data, which show the overall picture, you get to another conclusion!”. This equals to claiming that the real shape of the stone is different. This is a situation that is often found: what data to show and how lies on the thin border between rightfully leading the interlocutor towards the proper interpretation or, on the contrary, being deceitful, for example by not mentioning something. Eventually, you can put on the table other data and facts that outnumber or make irrelevant the first. This equals to putting a much bigger stone on the table, dwarfing the first. Facts and data, particularly in the scientific field, are fundamental and constitute the cornerstone of a discussion. ... But, as mentioned before, they do not need any rhetorical "art". So let’s see what we can do with the rhetorical art. Rhetoric, in fact, suggests further ways to argument, like, for example, by using what in Greek were called "topoi", literally, “places”. Topoi can be defined as "patterns of reasoning”, in other words, macro-schemas, strategies, which are “stored in our cognitive resources". Let us see the topos of “the more and less likely". It basically states that “if the most likely thing does not happen, then the less likely thing will also not happen.” For example: “If the greatest mathematicians have not been able to solve the Goldbach’s conjecture yet, how do you think you will?” Another example is the topos from the contraries. This example is by Aristotle himself: “Self-control is good, since lack of self-control is bad”. This topos is based on the principle of non-contradiction, for which A and non-A cannot co-exist. There are dozens of topoi and I strongly encourage you to explore them: they can act as a spark for invention, for deciding what to say, or as a checklist to see if you have covered all lines of reasoning. Another good way of “argumenting” is to make use of examples. Examples trigger an inductive form of reasoning of this kind: to support a specific claim, you introduce another claim, which in some way is similar to the first. By passing through an implicit generalization, the two are shown to be akin and then it is easy to say that what applies to one applies to the other and vice versa. Let us see an example: “Nuclear radiations can be dangerous, but do we really want to do without them? Also medicines can be dangerous: would we do without them? Nuclear radiations and medicines are shown to both belong to the set of “useful for the health though potentially dangerous things”. The fact that medicines are accepted is used as leverage to persuade that nuclear radiations should be accepted as well. Examples are “arguments by analogy” that persuade due to the striking evidence of the second claim being called upon to support the first. So my suggestion is: next time you discuss with someone or you write a paper or you sketch a proposal, ask yourself if there isn’t any “it is as if…” you can bring in your argumentation. Take time to find one. You will see how well it works.
