Karl Popper, the enemy of certainty, part 1: a rejection of empiricism
The effects of Karl Popper’s work are still being felt today both within and beyond the philosophy of science.
You might ask why we should care what an Austrian philosopher of science who has been dead for 18 years thought about the nature of scientific inquiry. Yet much of what Karl Popper contributed to the philosophy of science has now passed into mainstream thought, into the currency of that nebulous, tricky ontology known as “common sense”. In the case of philosophers such as Popper, their work is, in a sense, too recent to be able to evaluate with the level of hindsight that we might apply to more distant thinkers, such as David Hume, and yet it is worth attempting to unpack.
Born in 1902, in Vienna, the young Popper demonstrated a broad range of interests (music was a dominant passion) and an inquiring mind: he entered into the intellectual hotbed of Austrian culture, attending lectures by Einstein, investigating the psychotherapeutic theories of Freud and Adler, and becoming a Marxist. He decided at the age of 17 that the latter ideology was unsustainable, in large part as a result of an incident during his brief time in the Austrian Communist party, in which eight of Popper’s friends were shot by the police in a riot instigated by the party in 1919. When Popper, somewhat naturally, complained to party leaders about this, he was told that loss of life was inevitable in the runup to revolution: Popper disagreed, and this sparked his lifelong commitment to political moderation, tolerance and liberalism.
The search for truth was, Popper considered, the strongest motivation for scientific discovery. His role was to determine how we can ascribe truth to the claims made by science, religion and politics. He did not, however, become a member of the Vienna Circle, that group of intellectuals who, following on from the work of Wittgenstein (the Tractatus mark-one version of that philosopher) aimed at the unification of the sciences and the wholesale rejection of metaphysics. Popper’s antipathy to Wittgenstein meant that he was not invited to become a member of this particular group, but being cast in the role of the formal opposition seems to have honed his own thinking on logical positivism. Following on from Hume and the latter’s rejection of induction, Popper took a stand against an empiricist view of science, endeavouring to show via his rejection ofverificationism, and consequent espousal of falsificationism, how scientific theories progress. We will be looking at this more closely in future articles, but the fundamental principle of falsificationism is this: any contradictory instance to a theory is sufficient to falsify that theory, regardless of how many positive examples appear to support it.
Attempts to present theories such as Marxism, Adlerian psychology and astrology as scientific are subjected by Popper to his own analysis of falsificationism, and fail the test. It is perhaps worth noting that Popper’s own doctorate was in psychology, attained in 1928.
Popper’s work, therefore, was fuelled by a number of engines: a disillusionment with Marxism, the increase of Austrian fascism, which led to his move to New Zealand in 1937 and then London in 1946, and a distaste for the psychological models of the day. Popper’s concerns over attempts to present psychology as a science, in contrast to the approach demonstrated by physicists such as Einstein, provide the groundwork to his work on falsifiability. Einstein’s physics, which Popper regarded as somewhat unstable, nonetheless contains the parameters for its own falsifiability: we can say what it would take to render the theory false. This, Popper pointed out, was not the same for psychological theories, which are unfalsifiable in principia. The bulk of Popper’s work in this particular area was done in the 1930s, in The Logic of Scientific Discovery.
During his time in New Zealand, Popper wrote his principal political tract, The Open Society and Its Enemies, a two-volume work in which both Plato and Marx come under fire. He criticised historicist analyses, in which society proceeds according to fixed and predictable political laws, and claimed that such analyses formed the basis for both ancient and modern totalitarianism. Epistemology is directly linked to politics within Popper’s work: certainty forms the basis for totalitarian thought, and yet it is a certainty that is baseless if considered scientifically.
Popper died in 1994, having influenced the course of the philosophy of science throughout the 20th century. He remains one of the most significant commentators within the discipline, and the effects of his work are still being felt today both within and beyond the philosophy of science, connecting as they do epistemology, politics, and the scientific method.
The Virtue of Refutation
Popper’s philosophy of science was based on the principle that a theory cannot be scientific unless it is falsifiable.
When it comes to logical positivist analyses of the scientific method, Popper takes a metaphorical axe and hacks away at the roots: his critique of positivism is essentially a critique of induction itself.
Positivism stems from the work of the Vienna Circle, of Neurath, Carnap and Reichenbach, among others. It holds that the scientific method is based on verification, ie that a statement is only meaningful if it can be empirically verified or if it is analytic (the truths of mathematics and logic).
Empirical verification comes from induction. We seem to be pattern-matching creatures – when we have a theory, we cleave tightly to it. We go to considerable lengths to seek confirmatory instances of it. Unless we are scientists, and properly rigorous, we typically discount, explain away, reject falsifying examples. Yet following Hume’s much earlier critique of this methodology, Popper maintains that inductive logic is inherently flawed: just because the sun has risen every day until now does not necessarily entail that it will rise again tomorrow. One instance of the sun’s failure to rise will falsify the theory that “the sun always rises”.
The scientist should reject theories when they are falsified. For instance, Einstein’s theories generate hypothetical consequences which, if shown to be false, would falsify the entire theoretical structure on which they rest. Psychological theories, however, in their attempt to explain all forms of human behaviour, can continually be shored up by subsidiary hypotheses. Exceptions can always be found. On a Popperian model, psychology resembles magical thinking: if an expected result does not manifest, explanations can be found which explain that failure away, and thus the core theory remains intact. This, Popper considered, is a weak point – the theory cannot be properly tested if it is inherently unfalsifiable.
Popper gives the example of a man who saves a child from drowning, and another who lets the child succumb. Both can be explained in Adlerian terms: the first has sublimated his negative urges, and the second is still suffering from feelings of inferiority, and cannot. But if the theory cannot be disproved, is it therefore scientific? Popper argues that it is not.
I could not think of any human behaviour which could not be interpreted in terms of either theory. It was precisely this fact – that they always fitted, that they were always confirmed – which in the eyes of their admirers constituted the strongest argument in favour of these theories. It began to dawn on me that this apparent strength was in fact their weakness.
He goes on to say that:
Once your eyes were thus opened you saw confirmed instances everywhere: the world was full of verifications of the theory. Whatever happened always confirmed it. Thus its truth appeared manifest; and unbelievers were clearly people who did not want to see the manifest truth; who refuse to see it, either because it was against their class interest, or because of their repressions which were still “un-analyzed” and crying aloud for treatment.
To Popper, therefore, exceptions immediately falsify a theory, whereas confirmatory instances are just references to experience and thus possess no inherent logical merit. Falsification should thus replace induction as a core focus of the scientific method.
This is not to say that Popper believes that the pseudo-sciences, such as psychology are invariably wrong: they may hit on truths by accident, they may simply be insufficiently rigorous at present, yet are proceeding towards rigour, or they may explain things in a way that is not scientific. They may undoubtedly be interesting. With regard to the psychological theories of Freud and Adler, Popper himself remarked:
I personally do not doubt that much of what they say is of considerable importance.
All that Popper is claiming is that the underlying theories are not sciences, although they may one day play a role within a scientific paradigm, a view which seems to have enraged those who want to claim scientific status for sociology, for example.
Irrefutability is, Popper insists, a vice rather than a virtue. We should be looking at theories that are confirmed by risky predictions: those predictions which should have led to an instance that disconfirms the theory. Destructive testing is the only really viable scientific test: we should always aim at refutation, not confirmation, for confirmation is too easy and too weak.