The Mirror Test
Note — this was originally published with Merion West and can be found here — https://merionwest.com/2019/05/21/the-mirror-test-a-way-to-assess-philosophies/.
Relativism is romanticized in many corners these days. It has mutated into several unique strains, each of which condemns claims of objective truth with respect to a particular domain. Cultural relativists argue that there is no criterion by which we may judge cultural practices. Epistemological relativists (also called subjectivists, to whom we shall return) argue that there is no method by which we may distinguish truth from falsehood. And so on.
The allure of these doctrines is understandable. On the face of it, claims of objective truth, or aesthetic judgment, or moral superiority, seem arrogant, especially in light of the overflowing dustbin of errors that burdens history. Thought leaders of yesteryear had declared certain races inferior. Others had invoked angels to explain the motion of celestial bodies. Many had ostracized iconoclasts whose ideas we now take for granted. Looking back with our contemporary perspective, we recoil at our ancestors’ mistakes. So when proponents of relativism declare the inevitability of errors in purportedly objective claims, they have a point. But diagnosis is not the same as prognosis. By asserting that there is no such thing as objectivity, relativists drive straight off a philosophical cliff.
But it’s not obvious why. After all, can we not avoid errors entirely by declaring all truth claims to be on par with one another? Wouldn’t this cease those humiliating and often violent mistakes of the past?
We can’t, and it wouldn’t.
To understand why relativism cannot end error-making once and for all, I need to invoke one of the Tools of Reason. There is one such Tool that hasn’t garnered nearly the attention it deserves. I call it the Mirror Test. It is a method by which we may scrutinize a philosophy on its own terms. The Mirror Test runs as follows:
- Accept a philosophy as tentatively true.
- Apply the philosophy’s own terms to itself.
- Determine whether or not the philosophy survives its own criterion/criteria. If it doesn’t, then it has refuted itself.
Like all Tools of Reason, it becomes intuitive after some practice. Let’s run subjectivism through the Mirror Test algorithm and see what comes out. Recall that subjectivists’ claim that there is no method by which we may ascertain absolute truth about Reality. So, the procedure should go something like this:
- It is true that there are no means by which we may distinguish truth from falsehood.
- Because there are no means by which we may distinguish truth from falsehood, then there are no means by which we may determine whether or not the statement, ‘there are no means by which we may distinguish truth from falsehood’ is true or false.
- Following step (2), subjectivism calls for its own lack of credibility as a truth claim. We therefore have no more reason to accept subjectivism than any other competing philosophy, and we’re back to square one.
So subjectivism is refuted by its own criterion. What philosophy survivesits own criterion, and therefore remains (tentatively, always tentatively) viable? One example is critical rationalism, which is the idea that knowledge grows by the method of conjecture and criticism. That is, we take guesses at how Reality works, what it’s really like, and why it is so. Then, we criticize those guesses (read: theories) with methods ranging from experimental testing; to checking for logical consistency; to comparing their efficacy with that of rival theories.
Does critical rationalism pass the Mirror Test? You’ll quickly see that it does:
- Knowledge progresses by way of conjecturing how Reality works, and then criticizing those conjectures. Those that survive our criticism are accepted as tentatively true, while those that fail to satisfy our criticisms are rejected as tentatively false.
- The claim that knowledge progresses by way of conjecture and criticism is itself a conjectured theory about how Reality works and is subject to criticism.
- Following step (2), this epistemological doctrine, critical rationalism, is consistent with its own criteria, and therefore passes the Mirror Test.
To be sure, just because a philosophy passes the Mirror Test does not mean that it’s correct. Much like an empirical theory that has been corroborated by one experiment but is destined to be falsified by a subsequent trial, a philosophy could always be overturned for some other reason that has not yet been considered. The primary benefit of the Mirror Test is that we may immediately determine whether or not a philosophy is false.
Compare critical rationalism with another epistemological doctrine, positivism. This philosophy asserts that only statements about observations or predictions are meaningful. An application of the Mirror test runs as follows:
- Only statements about observations and predictions are meaningful.
- The claim of positivism, that ‘only statements about observations and predictions are meaningful,’ is itself neither a prediction nor an observation.
- Positivism, therefore, asserts its own meaninglessness.
While critical rationalism and positivism are both epistemological theories, only one passes the Mirror Test. Here we see the value of this Tool — it can sometimes tell us which doctrines among competing doctrines are patently false.
Why is the Mirror Test not more commonly applied? Many philosophical arguments would progress following its employment. The reason may be related to the old joke about asking a fish how the water is, and the fish answering, “What’s water”? In other words, while it is intuitive to consider the logical consequences of a philosophy in application to more distant concepts, it’s far less intuitive to take a philosophy and have it reach around to see the back of its own head.
To see the difference between applying a philosophy to other matters and applying it to itself, let’s examine another doctrine, this time pertaining to progress. One scientist, David Detusch, has recently claimed that, “The search for hard-to-vary explanations is the origin of all progress.” Let us call this philosophy ‘Progressivism’ (not to be confused with the political ideology of the same name). What I called the intuitive consequences of Progressivism are those that apply to, say, scientific theories. So, this philosophy would regard the ‘selfish gene’ theory of evolution as an acceptable explanation, since its components are hard to vary while remaining the same explanation. The theory states that, in the presence of scarce resources, those variants of a gene that are best at propagating into future generations will outcompete all other variants of that gene (the technical term for a gene variant is ‘allele’). Change any component of the previous statement, and the logic of the theory falls apart. That is what makes it hard to vary, and so, according to Progressivism, it is an acceptable theory.
On the other hand, consider the theory that angels are responsible for the motion of celestial objects. ‘Angels’ could logically be replaced by many other objects and leave the underlying explanation unchanged. The theory that vampires move planets and stars around has exactly as much merit as the ‘angel theory’. The ‘angel theory’ of celestial motion, therefore, is easy to vary, and, according to the progress philosophy described here, is an unacceptable explanation.
What I called the less intuitive consequence of a philosophy is the one discovered by applying the Mirror Test. In order to ‘see the back of the philosophy’s own head,’ we will run the Mirror Test one last time, now on the Progressivism philosophy:
- It is true that the search for hard to vary explanations is the origin of all progress.
- Because the search for hard to vary explanations is the origin of all progress, then the philosophy ‘the search for hard to vary explanations is the origin of all progress’ must itself be hard to vary.
- Any component of ‘the search for hard to vary explanations is the origin of all progress’ changes the logic of the statement, and so it is itself hard to vary. The philosophy therefore survives its own criterion. Namely, the Progressivism is itself hard to vary.
Employing the Mirror Test for Progressivism is likely a heavier cognitive load than applying Progressivism directly to other theories. But as I’ve implied, I’m not sure there’s any correlation between a Tool of Reason’s usefulness and the steepness of its learning curve. Our intuitions don’t determine what is true, nor what is philosophically helpful.
I hope you’ve acquired a new Tool today. Grab it, use it. See how far it takes you.