Remember the feeble but clever child that would inevitably come in last in every footrace of your childhood? And when he passed the finish line he would yell: "Last one wins!" And from there the argument would ensue.
Without agreed-upon rules or enforced norms you cannot have a meaningful footrace. The same is true for an argument: You and your opponent must agree on some basic rules. The following is a minimum list:
- Facts outweigh fantasies.
- Actions outweigh words.
- A statement may be either true, or undecided, or false.
- Mutually exclusive statements cannot be true at the same time.
- The truth of a statement is independent of its proponent and the number of its proponents.
- The cause must precede the effect in time.
- Every cause is an effect of some other cause.
- If the premises of an argument are true, and the logic of the deduction is correct, then the conclusion must be valid.
Lunatics do not abide by these rules, either unknowingly or deliberately.
Unfortunately, in the evolution of democratic society, we have reached a stage where ignoring an opinion is considered an undemocratic act. Consequently, we patiently listen to even the most lunatic ideas, ideas that not only lack evidence but that often go against massive evidence to the contrary.
This practice has had dire consequences: The reinforcement of the lunatic's confidence that his conviction represents a legitimate position. The conclusion by the underinformed that facts are fewer and less certain than they in fact are. The folly to take the lunatic's confidence as a measure of the strength of his claims. The abuse of our good will by people with nefarious agendas. The catering of desperate politicians to lunatic superminorities. The adoption of the fear-and-anger business model in the media. The readiness of governments to disinform their own citizens and those of foreign nations. ...
And so, the Protocols of the Elders of Zion, 9-11 conspiracies, birtherism. And so, holocaust denial, climate change denial, mass shooting denial, CoViD denial. And so, QAnon, the "stolen" 2020 U.S. election, anti-vaccine delusion.
But here is the thing:
NOT ALL TRUTH PROPOSITIONS ARE EQUALLY PROBABLE.
Would we give television time or newspaper space to someone who claims electricity does not work, or antibiotics, or bridges across rivers? To someone who believes water, or food, or gravity are social constructs? (Admittedly, the number of gravity deniers must be small, not because the evidence is literally just a stone's throw away, but because their lives must be so short.)
Example: Liberal vs. authoritarian
It is interesting how often authoritarians invoke their right to express their views (e.g. Klu Klux Klansmen, conservative clerics). While from a liberal viewpoint this is hypocrisy, it is a logically valid position:
The premise of liberals is that all opinions are valid. Consequently, a liberal must approve of the expression of opposing opinions and cannot engage in activities that would restrict such expression. (Consider the quote attributed to Voltaire: "I do not agree with what you have to say, but I'll defend to the death your right to say it.")
Authoritarians, on the other hand, can use a priori features (e.g. skin colour, gender, age, education) to make a judgement about validity of an opinion. Consequently, an authoritarian may oppose attempts to silence his opinions but can attempt to silence others.
It is easy to see that a liberal often finds herself at a (self-imposed) argumentative disadvantage.
Example: Philosophical objections
Philosophical objections can be construed against any and all rules of argumentation. Consider these two from the list above:
3. A statement may be either true, or undecided, or false.
But how about the following statement: "This statement is false." If the statement is true then it states that it is false. And if it is false then it states that it is true. And so ad infinitum. The problem arises from self-reference, a change in the contents of the statement through a statement outside of the system.
The Austrian mathematician Kurt Gödel (1906-1978) demonstrated that there in a self-referential statement instances may occur that make the statement complete ("This statement is true.") or make it consistent ("Another statement is false."), but do not make it both.
7. Every cause is an effect of some other cause.
The Scotish philosophyer David Hume (1711-1776) pointed out that the statement "Every effect has a cause." is only a belief based on past experiences and not on logical certainty. There might be effects without causes. Two examples: In creationism, the creator is an effect without a cause. The radioactive decay of an individual atom appears to be random, i. e. one cannot predict when the individual radioactive atom will decay.
Keep in mind that the absence of something cannot be proven in principle. And so a perceived creator might have hatched from an egg and "earth rays" might cause an atom to decay.
While these are valid objections, for all practical purposes they are immaterial.
Remember: If someone has made up her mind against you, there is nothing you can do to change her mind. Everyone is entitled to one's own opinion, but not to one's own facts.