Making the case for libertarian ideas can be a tough task when faced with people who have had half-truths and falsehoods pounded into their heads since childhood. But an interesting and powerful way of refuting such people's arguements is to point out any performative contradictions that they imply or that the person engages in.
A performative contradiction is as the two words imply: a contradiction that is demonstrated by a person's actions. For example, if I was engaging in the action of shoveling snow and I said "I cannot shovel snow", I would obviously be contradicting myself by shoveling snow.
The subject of free will dates back eons. Some may view it as a primitive construct to be done away with. But I think that its existance and importance is clearly self-evident, which is exactly why the concept can be found so early in history.
What we find is that those who wish to deny free will are engaging in a performative contradiction. It'd be a performative contradiction to say "I don't have free will". You would have just used it to express the opinion that you don't have it.
Denying the existance of free will is ironically proof of free will. No matter what one does to argue against free will, they will be engaging in a performative contradiction and therefore proving free will in practise.
In relation to the question of free will, one common debate that libertarians may find themselves in is one in which someone challenges the existance of self-ownership. This is yet another performative contradiction.
To say "I don't own myself" is inevitably a demonstration of one's ownership of oneself, as expressed in their control necessary to make the statement in the first place. To make the statement is to take a voluntary action over one's own self, and therefore simply reaffirms that one owns oneself.
The only possible rebuttal to this is to claim that people's actions are pre-determined (like a secular predestination), which is obviously false. People's actions are rather unpredictable, precisely because as individual self-owners, they independantly take actions as expressed in their control over themselves.
Another, somewhat similar method of arguementation is to deduce reducto ad absurdums, which is latin for reduction to the absurd. Performative contradictions can be considered a form of reducto ad absurdum, but the concept extends beyond them. Reducto ad absurdums often point out that the critisized idea requires an impossible scenario to be realized or that the critisized idea contains two contrary ideas within itself.
The reducto ad absurdum that arises in relation to a challenge to self-ownership is that it would be impossible for anyone to take any actions at all without self-ownership and the control that it implies. If you do not own yourself, then you do not control yourself, and therefore you are unable to take any voluntary action at all.
Some people, particularly those on the left end of the political spectrum, while they may often support the idea of self-ownership, tend to question the concept of property rights over material objects. But property rights over material objects technically is a consequence of self-ownership, which is one's property right over oneself. The obtaining of material property inherently results from people using their self-ownership to aquire and control them.
There are a number of ways in which this can be done. It could be done by simply finding previously unused resources, such as picking an acorn off of the ground - the ownership of the acorn is justified as a product of the application of self-ownership. The person has used their self-ownership in a way that brings a material object into their possession.
A performative contradiction that arises in this example would be if the person who picked up the acorn said "I don't own this acorn". In reality they possess the acorn and therefore control it.
What about objects which are not something that we can simply pick up directly from nature: such as homes, articles of clothing, cars, pharmacudical drugs, etc.? These are objects that result from labor, which is an application of one's self-ownership towards productive tasks. Natural resources were transformed through human labor to create something new. The property's ownership is justified by the mixture of one's labor (I.E. self-ownership) with resources.
Things get a bit more complicated in the case of employment. Employment is a contract that entitles the worker to payment for working for the employer. The contract is effectively a voluntary trade off between the employer and employee.
Instead of the worker owning the material objects or services that they produce, they are given money by the employer that generally amounts to the value of what the worker produced in exchange for what was produced. The opposite would be absurd: a steel worker getting paid in the steel that they produce, instead of wages as a trade-off for yielding the produced steel to the employer? Ridiculous.
The reducto ad absurdum becomes even worse when we consider the case of jobs that don't necessarily produce material objects, but services (such as psychology, counseling, education, sports, etc.). Of course, these services require certain resources in order to carry out.
However, the actual job of the teacher, for example, is the service of teaching rather than to produce material objects (although in a limited sense, teachers do produce material objects in terms of paperwork, but nothing much more than this). The teacher is in a sense being payed for the use of their self-ownership to appease the task of teaching.
The reducto ad absurdum that arises if we believe that the worker is entitled to own what they are payed to produce for the employer in this case would be even more radical then the previous one: teacher's being given ownership of the school's property in payment for teaching, instead of wages in exchange for the service of teaching? Absurd. Such an absurdity would imply that workers in service-type jobs are literally entitled to ownership of the buisiness that hires them.
Another vital means of obtaining property is voluntary exchange between individuals. Such an exchange is effectively a switching of property titles. Once again, it is manifested in self-ownership by the control necessary to take the action. This means of justifying ownership is based on the fact the two parties voluntarily gave up ownership of one thing to obtain the other. They expressed their self-ownership to give up one property title to the other.
To deny one's right to voluntary exchange is to deny one's control over their own property, and therefore erode their ownership over it. Indeed, without economic exchange, people would be doomed to living off of their own back yards. Eventually, there would be no human beings left on the planet if they were unable or disallowed to exchange with eachother.
It would be absolutely absurd when one realizes that it would require that each individual human being economically isolate themselves from eachother, required to build their own home, provide their own food, provide their own clothing, provide everything all by themselves. That would be true "isolationism", in a bad way. Of course, it's an impossibility because human interaction is a necessity for the survival of the species.
Some people, particularly communists, make the claim that "property is theft", and use this as an arguement against all property or private property. This is another blatant reducto ad absurdum. The entire concept of theft implies a property right by its very nature. You cannot have theft without an original just owner of the property. To claim that theft has gone on is simultaneously to imply that someone (the victim) has a legitimate private property right.
One virulent idea that has particular popularity in contemporary philosophy and politics is the egalitarian conception of equality, that is, absolute equality. This notion has been applied to everything from economics to gender, always being a logical absurdity when applied to real human beings.
The criteria necessary to have absolute equality is uniformity; absolute equality is the same thing as uniformity. Inherently, the more unequal people are with respect to eachother, the more diversity there is, while the more equal people are with respect to eachother, the less diversity there is.
Pure equality in economics would require that everyone in the world be payed the exact same paycheck, work the exact same hours, posses the exact same level of productivity, enjoy the exact same benefits, own the exact same property, share the exact same consumer preferances, and spend the exact same amount of their money.
Pure equality in gender would require that there be an identical number of men and women, that men and women split up their activites 50/50 in all circumstances, that men and women think the exact same thoughts and share the exact same traits in all respects. It easily implies total androgony, hermaphroditism as the norm.
In short, the egalitarian notion of absolute equality leads to endless utopian impossibilities no matter what aspect of life it is applied to.
A related fallacy is the theory of democracy. The theory of democracy claims that it is possible to have a government that is entirely based on the "consent of the governed" and therefore a government that is representative of "the people" as a totality. In reality, however, "the people" is not a uniform entity. It consists of individuals with varying thoughts, actions and traits of their own; different wills of their own.
The inevitable requirement of the theory of democracy is unanimous consent. There is no such thing as unanimous consent to the government. "The people" have conflicts of interest among themselves, and of course there is a conflict of interest between "the people" and the government.
There is an endless sea of individuals and groups who do not favor the government or a particular policy. When the elections are over, the people who did not consent to and do not agree with and the result are forced to be effected anyways.
What has occured in reality is that, at best, a minority group (numerical* majority - even the claim to "majority rule" is often suspect in light of the fact that we are dealing with numerical majorities rather than real majorities) has dictated their consent to the rest of the population. Whatever the government ultimately decides is going to effect everyone, regaurdless of their votes and consent as individuals.
Another nonsensical doctrine is the notion of post-scarcity, which is the idea that there is (or we can create) an environment in which the scarcity of resources no longer exist. It most certainly takes some huge illogical leaps of faith to believe this. If there was no scarcity, then anything we want could be manifested infinitely, like mana raining from the sky at the snap of our fingers.
Such a scenario is silly. The planet in which we live on is a scarce, finite object. The resources that spawn from it are therefore also scarce. While some resources are more or less scarce then others, nothing is truly infinitely available to us. We cannot have infinite apples. There is always some limit to such things. In short, the criteria for post-scarcity is infinity in terms of the material objects available to us on the planet - a starry eyed pipe dream.
The methods of pointing out performative contradictions and reducto ad absurdums can be extremely useful. Above we have used them to refute quite a number of ideas: that people don't have free will, that people don't own themselves, that there is no justification for material property, that government can be based on unanimous consent, collective or worker ownership of buisiness property or the products that they are payed to produce, the idea that property is theft, the egalitarian notion of equality, the theory of democracy and the idea of post-scarcity.