As the happiness or real good of men consists in right action, and right action cannot be produced without right opinion, it behooves, above all things in this world, to take care that our own opinion of things be according to the nature of things.
What are the facts? Again and again and again - what are the facts? Shun wishful thinking, ignore divine revelation, forget what 'the stars foretell,' avoid opinion, care not what the neighbors think, never mind the unguessable 'verdict of history' - what are the facts, and to how many decimal places? You pilot always into an unknown future; facts are your single clue. Get the facts!
Robert A. Heinlein
Time Enough for Love
. . . most of us have surprising gifts for believing contradictory things. But granting that we can do this, why should we seek to avoid it? The answer seems clear enough. It is because if we do not think in accordance with logical law, we shall not think in accordance with fact. The 'ought' is a hypothetical imperative; it tells us that we must avoid thinking illogically if we want to think truly. And this implies that the reality of which our thought is true is itself governed by logic. If contradictory assertions cannot both be true, it is because the reality of which they are asserted does not admit contradictory characteristics.
Reason and Analysis
In the broadest, most general, and least technical terms, rationalism is the view that all of our beliefs should be grounded in reason and evidence - that is, "facts".
This view has never been popular with conservatives: Galileo discovered this when he put forward a heliocentric (sun-centered) theory of the solar system. (The Pope mistakenly believed that the Earth was the center of the solar system, and sentenced Galileo to house arrest, thereby laying the foundations for today's culture war.) Climate scientists discovered this antipathy more recently when they pointed out that climate vandalism is both real and humanly-caused. Dr. Fauci discovered it in the course of trying to set rational pandemic policy in the face of Donald Trump's irrationalism, ignorance, and narcissism.
From motives of the economic self-interest of its wealthy owners, the corporate mass media have raised the omission and distortion of information to an advanced discipline, and most "pundits" harbor, at best, an extraordinarily weak allegiance to reason and evidence, preferring instead to remain employed. Even if this wasn't true, the mass media talking heads are scientifically, mathematically, and philosophically illiterate; and this means they should be preparing energetically for some other career rather than continually, and intentionally, misleading their peers.
Many have pointed out that we are very imperfect organisms when it comes to reasoning clearly. While this is unfortunately true, there is no significant or meaningful alternative to rationalism and the use of reason. In the end, all of the many attacks on reason, and the importance of reason, have made use of — reason. What other sort of credible attack would be possible? But we can and should utilize reason to improve our reasoning. This is one important aim of both logic, properly conceived, and of one branch of normative humanistic psychology.
Three related disciplines comprise the trunk and branches of rationalism. (For a diagram of this, see this link.) On this metaphor, the trunk and roots are provided by philosophy. Philosophy sets forth the foundations of rational values, investigates the nature of logic, and also provides the conceptual foundations for the two other branch disciplines that make up rationalism: science and mathematics. While there is much lively and interesting debate concerning the nature of philosophy, logic, science, and mathematics, in the end these are the tools that have provided the best understanding of the nature of the universe — and it is philosophy that has provided our best understanding of morality and life purpose. (Though there is also much of value - together with confusion and error - to be found in world religions.) If a majority of people knew no mathematics and no science, this would be considered a profound and crippling sort of illiteracy indeed. Yet the vast majority of people actually are philosophically illiterate - and this is even worse.
Rationalism has, or at least should have, a special place of honor in all democratic nations. The foundations of democracy lie with a well-educated citizenry, and one carefully and thoroughly trained in the methodologies of reasoning from evidence to good conclusions. To put this another way, the citizens of democracies need a full set of tools for successful critical thinking. These tools are properly supplied by philosophy, science, and mathematics, the component disciplines that together comprise rationalism. In pseudo-democracies, such as that of the United States, propaganda has become highly sophisticated, making possession of the tools of critical thinking all the more essential; yet nowhere is critical thinking carefully and thoroughly taught as the indispensable bedrock of a good education.
Moreover (and this goes a long way to explaining why critical thinking isn't taught), the philosophy of economics and the philosophy of politics are essential in assisting the citizenry of a democracy in understanding the nature of a genuinely democratic society — and economy. Unfortunately, at present the philosophy of politics, for example, is so little taught and so poorly understood that the average American doesn't truly understand such basic concepts as authoritarianism and democracy, and the differences between them. And even a college education doesn't necessarily help: classes in the philosophy of economics and the philosophy of politics aren't required even of philosophy majors, when they are even taught. Corporate antipathy is, of course, at work here; but so is philosophical illiteracy. For now, the blind lead - if that is the word - the blind.
We suggest that readers interested in learning more concerning rationalism begin with some good non-technical reading. A wonderful place to start would be with Brand Blanshard's "Four Reasonable Men", a set of four biographical portraits of men who were each exemplars, in their own way, of the reasonable, and therefore reasoning, temperament. What can be hoped for from the active cultivation of reason in life is very inspiringly illustrated by philosopher and rationalist Blanshard throughout this incredibly illuminating book. Blanshard also provides a really delightful and enlightening account of rationalism in philosophy in Chapter Two of his book Reason and Analysis.
Having then got some sense of the truly central importance of reason in life, the reader will find some concrete, practical tools provided by John Chaffee in his book "The Thinker's Way". In fact, Chaffee's book might almost be thought of as a practical manual explaining in greater detail how to do what Blanshard so persuasively recommends.
One way to then continue would be to go on to acquire a deeper understanding of philosophy itself. Probably the place to begin would be with an historical account of how and why philosophy first developed. Moving on from there, the reader will be greatly aided by an understanding of what the main branches of philosophy are, and what subjects they are most concerned with. Two resources will be helpful in meeting these objectives.
The first is a fascinating and highly readable historical introduction to philosophy: Will Durant's "The Story of Philosophy". This book will go far toward preparing the reader to undertake more advanced reading in philosophy.
The second is Mortimer J. Adler's book "The 4 Dimensions of Philosophy", which offers, essentially, a philosophy of philosophy (which is known technically as metaphilosophy). We especially like Adler's emphasis upon 'dialectic'. As Adler uses it, this term refers to what is perhaps the most important type of metaphilosophy, which has as its aim the ideologically neutral clarification and description of the philosophical questions that should always be as clearly stated as possible antecedent to actual discussion. The idea here is to be as clear as possible about what is actually at issue before getting too far underway. It should be philosophically scandalous to offer answers without first being clear what the questions are; yet this is somewhat common even within the bounds of philosophy, and nearly universal outside of its bounds.
Edmund Husserl and Brand Blanshard were the foremost exponents of rationalism in the 20th century, and are here regarded as the 20th century's most important philosophers. Blanshard's extraordinarily clear and well-written "Reason and Analysis" discusses how and why much 20th century philosophy ended up in a ditch, and points in the right direction. Colin Wilson's "Introduction to the New Existentialism" is an intensely interesting and highly readable first introduction to the thought of Husserl (who is himself, unfortunately, an especially dry read). Interested readers might then continue with Don Idhe's "Experimental Phenomenology", to better understand how, why, and when to do phenomenological analysis, and then Joseph Kockelman's "A First Introduction to Husserl's Phenomenology", which, though quite good, unfortunately doesn't do enough to motivate reader interest in the topic, and is therefore probably better read as a third introduction.
A more in-depth defintion and discussion of the the term "rationalism" may be found here.
In addition to reviews of the books by Durant and Adler mentioned above, the Everything Progressive Field Guide to Philosophy will offer many fascinating additional resources.
"We are not afraid to follow truth wherever it may lead, nor to tolerate any error so long as reason is left free to combat it."
The Editor / Everything Progressive