If I were to give my definition of libertarianism, and we can all play the parlour game, I would say: Libertarianism is an individualistic political philosophy, based on one primary ethical imperative; non-aggression.
Prior to this may come a belief in individual liberty as a natural right, a product of an inalienable property we have in ourselves, or there may be no such belief at all, but instead a rational, utilitarian assessment, that a society governed by non-aggression would be for the greater good of the greater number, or there may be no such intellectual ruminations, but rather a more heartfelt, visceral impulse to resist the tyranny and coercion of others, a flintlock of defiance, ever-ready to spark within us, or a combination of all the above, or I know not what, but however this may be, whatever the prior motivation, it is the adherence to and approval of, the axiom of non-aggression which defines the individual a libertarian.
Using the twin methods of logical deduction and drunken discourse, libertarians attempt to agree upon the implications extending from this axiom, with regard to society, its laws and institutions, as well as to the individual person and his relations with others, always bearing in mind the limitations placed upon us by nature; the uneven distribution of abundance and scarcity, and what the scientists can tell us of such matters.
And then crashing into our speculations comes the unavoidable reality of the state and its power, and the strictures it has placed, through regulation and the threat of force, on our freedom of action in almost every direction. We consider its legitimacy, or lack thereof, and also consider war and crime, the government, the democratic system, the administration of the law and the functioning of the economy, especially with regard to the effects of state action. We are individualists, and our discussions reflect this.
Interwoven is a debate on our prior motivations as noted above, for the differences between these are reflected in other differences of opinion. We converge at the axiom, but our starting points are different and our conclusions often likewise. Supplying points of reference is that body of work, we may call the Libertarian Tradition; the writers, thinkers and doers, extending back to the Enlightenment and beyond, who have explored and mapped the territory around us. They each take their own paths, and concern themselves more with one thing than another, and, of course, as individual libertarians we are free to branch out for ourselves, as long as we can trace our way back to the non-aggression axiom.
Now let us consider how each of us relates to this tradition and its expression, how we are bound in some way to those other souls, who for whatever reason and through whatever window, have looked at the world and drawn the same conclusions, that freedom is a prerequisite for true happiness, that it is an imperative of our very nature, and to assert these values and resist their infringement is a right we may claim, if not an obligation we evade only through an abdication of moral rectitude.
In summary, libertarians seek to establish, not only in theory but in fact, a society where non-aggression is the rule, and the defence of liberty is supported by the law, and each individual is free to pursue his own betterment, through voluntary exchange and thus, happily, howsoever incidentally, through service to others, in short: we seek a society where liberty reigns and justice is done.
Cross-posted at the Pro Liberty website