It works this way. All liberals start off with a belief that the individual should be self-created by their own will and reason. This means that liberals have to clear away unchosen impediments to individual will, such as race, gender and class.
But this leaves a fundamental problem. How can you possibly regulate a society made up of millions of individual wills, each pursuing their own selfish desires? This is the question asked by Australian liberal Clive Hamilton, in his essay The Disappointment of Liberalism. He writes that,
this essay is a prelude to answering the question of how we can reconstruct the social in an individualized world. In a world where we are no longer bound together by our class, gender or race, why should we live cooperatively?
Mainstream liberals have given two basic answers to this question. Right-liberals (classical liberals) believe that society can be regulated by the “hidden hand” of the free market. In this theory, people can pursue their economic interests selfishly, and yet still generate positive outcomes for society as a whole. Right-liberals therefore have a focus on Economic Man and would prefer that the state didn’t interfere with and distort the operations of the market.
Left-liberals reject the idea of the market as a means of regulating society. They see the market as generating unequal outcomes, and they want a more deliberately rational regulation of society. They therefore prefer society to be regulated either by the state or by local communities.
So, the most basic left/right distinction is between those on the right who prefer market regulation and those on the left who prefer state/community regulation.
There is, however, another important distinction to be made. If you were to imagine a pure liberalism, in which individuals were entirely autonomous and unimpeded, a centralised state would have little role. Therefore, the more radical liberals, of both right and left, who want to achieve a pure liberalism straight away, will be “small state” or “no state” liberals.
So the political spectrum goes like this. On the right you have those wanting regulation by the market and on the left those wanting more deliberate regulation by the state or local community. In the middle you have those accepting a larger role for the state and on either radical end you have those opposing a large role for the state.
So, on the far left you have anarchists (left-libertarians), then on the centre-left you have social democrats (left-liberals), then on the centre-right you have mainstream right-liberals like the American Republicans or Australian Liberals and on the far-right you have Ayn Rand type right-libertarians.
Notice that the opposite ends of the spectrum have something in common in virtue of their radicalism, namely a libertarian opposition to a central state.
All that remains to be explained is where conservatives, communists and fascists fit in to the spectrum. As noted, the terms “left” and “right” refer to a distinction within liberalism. Therefore, conservatism doesn’t fit within this spectrum at all. That’s why conservatives will sometimes find themselves agreeing with left-wing criticisms of an unregulated market, but at other times with right-wing criticisms of an interventionist state.
Marxist communism is an interesting case. I reserve judgement, but I expect it fits on the spectrum as a form of radical leftism. It’s true that Marxists want to establish an authoritarian state (the “dictatorship of the proletariat”) to achieve their aims, so this might seem to go against the idea that the more radical liberals want a small state. However, Marxists believe that the dictatorship of the proletariat will only last for a limited time and will then give way to the end of history in which there will be no state. So ultimately Marxism does seem to fit in well as a form of radical leftism.
I reserve judgement too on the exact place of fascism within the polical spectrum. However, I expect that it doesn’t fit on the spectrum at all, as it’s not a part of the liberal mainstream. Fascists don’t follow the mainstream liberal belief in a society made up of millions of atomised wills, each following its own desires. The triumph of human will, its highest realization, for fascists, seems instead to be the practical assertion of a collective will, itself embodied in the will of the leader.
Perhaps the notion that fascism is “off the spectrum” explains why it seems to incorporate aspects of both left and right wing politics.