Not All Viewpoints Are Reasonable
In discussing reason, we can draw from the first paragraph in its Wikipedia entry:
Reason is the capacity for consciously making sense of things, establishing and verifying facts, applying logic, and changing or justifying practices, institutions, and beliefs based on new or existing information. It is closely associated with such characteristically human activities as philosophy, science, language, mathematics, and art and is normally considered to be a distinguishing ability possessed by humans. Reason, or an aspect of it, is sometimes referred to as rationality.
It goes without saying viewpoints that do not conform to facts or logic are unreasonable. When unreasonable viewpoints are included in a discussion, it diminishes the ratio of reasonable information to total information in the discussion. In common parlance, this is known as decreasing the signal-to-noise ratio. Noise is being added to signal.
What good does this achieve? Is there anything intellectually worthwhile that comes from countenancing unserious, illegitimate viewpoints in an intellectual, reason-based discussion? Is there any value to allowing reasonable discussions to devolve into incoherence, where noise drowns out all signal?
If we are having a discussion about rocketry and orbital mechanics, does it help to have a member of the Flat Earth society come by to offer input? If we are talking about carbon dating analysis of an archaeological site that appears to be 10,000 years old, does it benefit the discussion to have someone who insists the Earth is 6,000 years old come along and offer input? If we are talking about nutrition and health in human children, do we gain anything from hearing out the Breatharians?
Of course the answer is “no” in all of the above situations. Expanding viewpoint diversity to include discredited and nonsensical ideas serves nobody except, perhaps, anyone personally benefiting from disseminating those ideas. Yet, self-proclaimed free speech absolutists and advocates of heterodoxy would tell you unreasonable ideas should be included. They may stop short of advocating for Flat Earthers to be part of serious academic discussions, but they draw their lines well short of reason.
There Are Reasons For Viewpoint Diversity
Human history is rife with examples of the silencing of dissent. Fascism and authoritarianism have risen and fallen. Kings and aristocrats have been immune to criticism from the common folk by way of oppressive laws. Theocracies have imposed arbitrary, irrational rules on people derived from arbitrary, irrational interpretations of ancient religious texts. Science has been deemed heresy, and people seeking to expand human knowledge have been burned, beaten, tortured, and put to death.
Another valid reason for viewpoint diversity is building toward academic consensus. Recent astrophysical data about gravitational waves provide an example of this. As of this writing, one of the more recent major gravitational wave events resulted from a pair of neutron stars spiralling into each other in a collision of cosmic proportions whose gravitational wave signature was detected across the vast intergalactic distance here on Earth. Electromagnetic radiation was also detected from this collision and, after traveling a distance of 130 million lightyears, arrived some 1.7 seconds after the gravitational waves. If gravitational waves travel at the speed of light — as is widely hypothesized — why the delay? No doubt there is some diversity in viewpoints as to the source of this delay, and the more precisely we try to isolate the cause, the more informed and nuanced the viewpoints become. However, all serious viewpoints on this matter conform to the process of scientific inquiry, attempting to merge theory and data. The more reasonable viewpoints the experts hear about the cause, the more likely they will be to find the correct explanation.
These are good reasons to advocate for viewpoint diversity and the freedom of speech. But, as we have already seen, reason lies somewhere between oppression and unmitigated viewpoint diversity. Reason, itself, must be what mitigates viewpoint diversity. In the previous example, where theories are being created and evaluated from empirical data and the scientific method, reason is already baked into the discussion. Astrophysicists are not considering input from wizards gazing into crystal balls to help them formulate their theories.
An Assumption of Reason & Not All Rationality is Equal
All of the above assumes that our goal is reason. This is not everybody’s goal, but it should be the goal of such institutions as courts of law and credible institutions of higher learning. It need not be the goal of propagandists or fanatical shriekers on streetcorners. Human progress is not built on the words of streetcorner fanatics, but it can be evaluated in how our laws treat them. It can be evaluated in how our universities come to understand and describe the social conditions that lead to fanatics raving on streetcorners. It can be found in how well science can diagnose and treat these streetcorner ravers.
Freedom grants the fanatic the right to exist. The right to rant and rave. Sensibility relegates that behavior to the public square, not the public library. In keeping with reason, it becomes apparent, too, that not all the ravings of all the fanatics, nor all the irrational propaganda of all propagandists is equal. They may all be equally illogical and unreasonable, but they are not all equally deleterious to the wellbeing of humanity or the planet. Given this disparity, it makes no sense to apply a signal-to-noise ratio balance to the decision of whether to countenance irrationality when irrationality is already accepted. If one irrational voice is let in, then all must be let in, lest a particularly damaging form of irrationality come to dominate. Where one fanatic may rave, all fanatics must be permitted to rave. So, too, must reasonable people be able to speak.
This liberal approach to speech need not apply when irrationality is not countenanced and reason is the objective. There is no need to give space to discredited ideologies, religious folly, psuedo-scientific sophistry, or any political agenda at odds with reason just because you give space to rational ideologies, logic, scientific inquiry, or reasonable political agendas. Heterodoxy must take a backseat to rationality in such arenas if reason and social progress are to be advanced efficiently. No amount of rhetorical strong-arming should be allowed to force open the doors of the academy, the court of law, or any other ostensibly reason-based endeavor to retrograde interests. To do so is to actively oppose progress.