Philosophy is the study of the ultimate nature of things. All science, generally speaking, is a knowledge of things through their proper causes. One has "science" only when one understands the cause or reason for the particular phenomenon of which one is inquiring. Philosophy, as you know, is a not an experimental or emperiometric science, which pursues the proximate causes of things, but is rather the science of the highest causes. It is a knowledge of things through their first or ultimate causes. The goal in philosophy is to pursue primary principles and their implications, and so its method, fundamentally, is dialectical reasoning.
It is for this reason that the true philosopher is not so much interested in whether or not his conclusions belong to any particular school of thought. What matters most to the genuine philosopher is whether or not his conclusions are true. That is why first principles are of the utmost importance to him. Philosophical thinking is reasoning on the basis of first principles.
Contrast this with ideological thinking. If one begins with the premise that knowledge is impossible, since reality is unknowable and unintelligible, then science becomes a fiction, a creation, an ideological construct that has the effect of making sense out of reality, which is otherwise unintelligible. So all we have in this world are particular perspectives or ideological constructs through which raw data is interpreted and given meaning. And because reality is absurd and unknowable, there are no objective causes that account for supposed "effects", and thus there is no permanent standard by which to measure the "truth" of a particular perspective or construct. They are all equally fictitious.
An ideological construct comes as a package that contains all sorts of things, such as starting points, assumptions, premises, conclusions, prejudices, etc., and it is through this package that the world can be interpreted. The problem, however, is that if one does not know how to think on the basis of primary principles (principled thinking), one will be unable to critically evaluate the ideological superstructure through which one interprets data. Rather, one will be critical of things on the basis of the ideological package, and thus feel as if one is a free and critical thinker, but one isn't quite sure whether the ideological package contains some rotten items that should be discarded.
Radical Feminism, Marxism, Fascism, and Historicism are examples of ideologies. Radical Feminism, for example, begins with the idea that all of history is a dialectical struggle between male and female, and all current institutions, laws, customs, etc., are the result of this struggle and can only be correctly interpreted in the light of it.
Most women are not radical feminists, even women who call themselves feminists. But the feminist with "ideological lenses" will look at the world and see it according to the shade of those lenses. If the predominant idea is that everything is about male domination, then news of a school yard shooting in which a number of females are shot and killed will inevitably be interpreted as confirmation of the ideology. Other news items documenting only male deaths, for example, are conveniently left in the penumbra, since such data does not readily blend to the rhythm of the ideological orchestration. It fails to confirm the theory, so it is ignored.
Very few people today have learned to think on the basis of first principles, which is why classical philosophy is not a very popular subject, at least not as popular as it was during the 40s, the 50s, and the 60s. Ideological thinking has more appeal to some because it involves less work. One does not have to spend years reading the great works of the great thinkers. All one has to do is buy the ideological package and one has something by which to make sense out of the world. It is quick and easy, like instant Oatmeal or a McDonald's Drive Thu.
There are Left Wing ideologues, Liberal ideologues, Right Wing ideologues, Conservative ideologues, Feminist ideologues, Marxist ideologues, etc. This does not mean, of course, that anyone who votes Liberal is an ideologue, or that anyone who is a conservative is an ideologue. There are conservative thinkers who are honest philosophers that reason on the basis of first principles, and the same is true for some liberals. But true thinkers are few and far between today.
Most of us are familiar with Liberal ideology only because it permeates Hollywood film and contemporary media. In this particular package, conservatives are depicted in a specific light. Whether or not the depiction is true to the facts, conservatives are, for the most part, portrayed as intolerant, narrow minded, bigoted, capitalist, environmentally reckless or indifferent, fanatically religious, Republican, pro American, pro military, opposed to gun control, possibly violent or open to violence. Liberals, to the contrary, tend to depict themselves as tolerant, open minded, inclusive, left leaning or socialist, environmentally conscious, peaceful, secular, Democrat, relatively anti-establishment and anti-American -- or highly suspicious of American motives.
When a gun wielding mad man walks onto a school campus and begins shooting everyone within his purview, most of us naturally expect him to be a bigoted, right wing, misogynist religious fanatic, angry that the world disregards the "will of God", and who believes he has a mission to punish it, or something to that effect. But Kimveer Gill, who opened fire at Dawson College this year, was nothing of the sort. What is noteworthy is that his complete profile was missing from media coverage of the event. Gill described himself as someone who dislikes: animal cruelty, the American government, anyone who supports the American government, Religion, God, Capitalists, f***ing religious people who think they know everything...and then they stick it in your face cuz' they think they know everything (they don't understand that they're just a bunch of little sheep), Catholics, Church going a**holes, Bible thumping know-it-alls, all priests, republicans, and homophobes.
Now this is not to suggest that left leaning people have a propensity to violence, or that the media is responsible for this rampage. Rather, it is to provide another example of ideological thinking. The facts in this case did not fit the theory, or the ideological construct that dominates the modern media, and so the facts were deliberately left out of the story. Had Gill been a pro American, religious, right wing misogynist, we'd all have heard about it by now, since it fits nicely into the Liberal ideological package that we are expected to embrace, if we are to consider ourselves truly enlightened.
Also, this is not to suggest that there is no such thing as right wing ideology. Many conservatives think within an inherited package that contains all sorts of goodies that vilify the opposition and filters data so that what confirms it is allowed free passage, while what makes things more difficult and obscure is left outside. That is why it is very important not to be too quick to jump on the bandwagon of a particular party. We all have a need to belong, and sometimes we will take on certain thinking patterns just to satisfy that need. The important thing, though, is to fall in love with truth, and above all to learn to ask questions, to think logically, and to pursue primary principles in a spirit of humility that is ready and willing to conform to their demands, whether or not some of them turn out to coincide with something liberals have been calling for, or something conservatives have stood for in the past.