The Ninth International Zoom Conference on the Philosophy of Sir Karl Popper, March 2025
Peter Lugten
Sir Karl Popper was an exponent of the “Correspondence Theory of Truth”, whereby a statement “x” could be said to be “true”, if and only if, it corresponds to the fact, x. In several papers, I have tried to show that the correspondence theory has weaknesses with respect to several problems. These include the regulatory nature of truth, which can never be attained, but only approached, the uncertainty concerning the exact nature of objects which are always in flux, the indexicality of an object’s position in the universe, and the evidentiary basis on which a belief may be held to be justified. There is also the question, as I pointed out, of ‘knowledge content’; whether a statement that is false by a small extent can be more useful that a ‘true’ statement that is vague by a greater extent.
(This differs from ‘truth content’, as discussed by Popper, whereby the statement “Today is Monday”, made by you on a Wednesday, is at least correct insofar that it is not Tuesday, or Thursday, etc. The ‘knowledge content’, unlike the ‘truth content’ would be greater on Tuesday than it is on Monday, in this example, because your statement is then only one day off, not two). In any event, the Correspondence theory of truth is so at odds with the dictionary definition of truth as being 100% complete, certain and self-consistent that confusion is bound to result. The Inversion Theory of Truth resolves these difficulties by relocating truth out of the subjective realm of conscious experience (Popper’s World 2) and placing it into the objective world as it is in itself, Popper’s World 1. Here it can never be known as a 100% enantiomorphic subjective mapping, but only through an active biological process of subjectivism that introduces an essential (as in unavoidable) degree of falsehood. Subjectively generated statements about World 1 can therefore never be said to be ‘true”, but, instead, can represent our ‘best knowledge’ of the true state of World 1.
An exception to this rule is made for purely introspective statements, such as “I am happy”, where the truth is a part of our subjective experience.
Popper reacted against the historical preoccupation of philosophy with essences, the true nature or the indivisible form of a thing which we intuitively grasp. To know a thing is to know its essence, said Aristotle; a sentence describing the essence of a thing is its definition (OS, Vol 2 p.10-15). Popper considered the sentence “A puppy (the defined term, DT) is a young dog (the defining formula, DF)”. As a rule, he noted, the DF is longer and more complex than the DT, representing its essence, which must be exhaustive and specific to the DT. To get the DF correct, avoiding any possible exceptions to the definition, is problematic. Plato said, and Aristotle seemed to agree, that we grasp the Idea with our unerring intellectual intuition, using our “mental eye”, not our senses, and then we can describe and define it. But this opposes modern science, where we look for the truth but can never be sure to have found it. In modern science, we read the sentence not from Left to Right, but from Right to Left. We start with the DF and ask a label for it. This is a Nominalist interpretation, as opposed to Essentialist, with the DT being just a shorthand expression for a complex idea.
Popper famously maintained that instead of “a young dog” being the definition of “a puppy”, a puppy is what we call a young dog. It is to the nature of what traits young dogs possess that science directs its attention. Popper insisted that our experiences and intuitions can never establish the truth of any theory, nor a grasp of its true essence. Science doesn’t progress through the gradual accumulation of essential information, but through advancing theories, testing them, and replacing those that are falsified. This way, instead of leading to an essentialist definition of the scientific solution, we get a falsifiable statement that represents the best of our knowledge at the present. Aristotle would have dismissed this as mere opinion, but, nevertheless, the nominalist definition of the scientific solution is far superior to the essentialist one: it is sophisticated enough to admit that it is necessarily vulnerable, and yet it demands our effort to improve it over time.
That Popper’s take on essentialism is relevant to my Inversion Theory of Truth was brought home to me by the discussion following my presentation in September’s 8th Zoom conference on the philosophy of Sir Karl Popper. Having made my case that any non-introspective sentence, as a member of Popper’s subjective World 2, should be described as ‘best knowledge’, shunning the epithet ‘truth’, I was countered with the following examples of ‘true’ statements, for which the Correspondence theory was held to be unimpeachable.
You could say that if I turn around and observe my dog sitting on the mat, my statement “The dog is sitting on the mat” is more than best knowledge, it is perfectly true. Or you could say, holding up an apparently full plastic water bottle, “I am holding this bottle of water”: truth as a statement is generally applied without the epistemological baggage of deeper refinement. Should it matter whether the dog is in fact an Irish setter whose grandsires included a mix breed, and that of its apparent genetic constitution, 99% consists of its microbiome, and, far from being a typical dog, it has a rare disease just beginning to affect its parathyroid gland…Does it matter that you, being colour blind, identify it as a brownish grey dog, when everyone else agrees that it is red? Does it matter that we don’t know how much water is in the bottle, or that some percentage of that is deuterium, or whether it has been adulterated with another clear fluid? As one person noted: “This appears to be a problem of realism and nominalism”.
I agree and would argue that in the “true sentence” “The dog is sitting on the mat”, the word “dog” is being used as describing the “essence” of the thing that is sitting on the mat – the thing that is undoubtedly, truly, sitting on the mat. But, to paraphrase Popper, “the dog” is not the DT of the truly knowable essence of the thing sitting on the mat; “the dog” is just what we are calling the not fully knowable thing that is sitting on the mat.
Popper discusses “basic statements”, or “observational statements”, a class of statements (true or false) which we can assume to be of unquestioned empirical character, that state the existence of observable facts within some narrow spatio-temporal region. (C&R, pp. 385-388) He had originally used the term “empirical basis” for these. They have in common that they may serve as tests (potential falsifiers) for empirical theories, the empirical basis for which, he argued, was far from firm. Indeed, the apparent data being observed as facts are always interpretations in light of theories, and therefore affected by the hypothetical character of all theories.
From this we can see that such statements are incapable of capturing the “essence” of their subjects. So, Popper wrote, “the statement ‘Here is a glass of water’ cannot be verified by any observational experience. The reason is that the universal terms which occur in the statement (‘glass’, ’water’) are dispositional: they ‘denote physical bodies which exhibit a certain law-like behaviour’. What has been said here about ‘glass’ and ‘water’ holds for all descriptive universals. The famous cat on the mat so much beloved by empiricists… is an entity even more highly theoretical than is either glass or water. All terms are theoretical terms, though some are more theoretical than others’’.
He goes on: “Singular statements about observable facts can be included into our ‘empirical basis’ [or basic statements] – ‘This clock reads 30 minutes past three’. That the instrument is a clock cannot be finally established or verified, no more so than that the glass before us contains water. But it is a testable hypothesis, and we can test it in a laboratory”.
And, on C&R p.119, again, quoting from his ‘Logic of Scientific Discovery’: “every description uses …universals; every statement has the character of a theory, a hypothesis. The statement “here is a glass of water” cannot be (completely) verified by any sense experience, because the universals which appear in it cannot be correlated with any particular sense experience…By the word ‘glass’, for example, we denote physical bodies which exhibit a certain law-like behaviour; and the same holds of the word ‘water’.’ He then adds: “I do not think that a language without universals could ever work; and the use of universals commits us to asserting, and thus (at least) to conjecturing, the reality of dispositions – though not of ultimate and inexplicable ones, that is, of essences”.
When using the Correspondence Theory of Truth, the sentences “The dog is sitting on the mat”, and “I am holding this bottle of water” are both essentialist in nature. The dog represents the ‘essence’ of the thing sitting on the mat, the bottle of water the ‘essence’ of what I am holding. This is inescapable if the sentence is going to correspond to the truth. The sentences are descriptions of their respective essences, just as much as ‘a young dog’ is a description of the essence of ‘puppy’. It is ironic that Popper, in his attack against essentialism, gives us these examples of the essentialist nature of the Correspondence theory. Popper would seem to agree with my assertion that we cannot know, or verify, the truth about the bottle of water, let alone the much more complex dog on the mat. The Inversion Theory, on the other hand, is more properly nominalistic. The essence of the dog, and of the bottle of water, are both theories, or tested opinions, that could be falsified, never verified. They represent our best knowledge at the time the statement was made. It is the ‘essence’ of the Inversion Theory, as it were, that it takes truth out of the subjective level, out of sentences, where it doesn’t belong, and puts it instead in the objective state, that corner of World 1, to which the sentence refers.
In conclusion, I’ll reiterate: since the subjective nature of sentences and statements incorporates essential falsehood, it is logically wrong to claim for them that they can be true. While many statements can be made under the claimed mantle of truthfulness without any problem arising, eventually, this mistaken habit will confuse people into thinking an idea, theory or concept to be objectively true when it is dangerously not so. Statements such as “The State is the march of God through the world” lead to “Might is right!”, and “God is almighty!” to the terrorist’s final cry of “Allah Akbar!”, for example. By substituting ‘best knowledge’ for scientific ‘truth’, and even ‘uncertain knowledge’, for metaphysical ‘truth’, we realize more emphatically that each one of us is responsible for assessing the relationship to falsehood of any claim before we decide to believe in it. As a corollary to this, if this was universally accepted, then when we meet people who hold beliefs different to our own, we could not dogmatically dismiss them as being wrong, which can lead to fights, and even war. When we all acknowledge the possibility of error in every opinion, we all should be better able to extend tolerance to other views, which leads to peace and even cooperation. It is hard to make such a claim for the assumption of an absolute truth that is known to correspond to the facts. The Inversion Theory is superior: I rest my case.
References:
The Open Society and Its Enemies, Vol 2: The High Tide of Prophecy. Hegel, Marx and the Aftermath. Princeton University Press, Princeton, NJ, 1963
Conjectures and Refutations: The Growth of Scientific Knowledge. Harper Torchbooks, Harper & Row, New York, 1963 [originally published by Basic Books, NY, and Routledge & Keegan Paul, London, 1962]
Scholarship of Fools Philosophy 