We have already seen how Popper suggested
that we could erect a boundary between science and metaphysics at the point of
falsification, but the implications of this choice reach further than might be
expected. If we choose to enforce Popper’s milestone, then Intelligent Design
has absolutely no business claiming to be part of science – but there are many
ideas currently considered science which must equally be excluded in this
scenario. We will find ourselves faced with a difficult choice – enforce Popper’s
milestone and science must ‘clean house’ and set aside anything that belongs in
metaphysics, or else follow Feyerabend’s lead and accept that there is no
viable boundary condition for science.
Remember Popper’s argument that a universal theory can be falsified by disconfirming evidence, and that a theory that cannot be falsified is therefore metaphysics and not science. Clearly, in the case of Intelligent Design there is absolutely no question at all of falsification, and therefore ID belongs in metaphysics and not science by Popper’s milestone. It is also worth noting that ID is couched in terms of an ‘ultimate cause’, and the idea of assigning such an ultimate cause has classically been the domain of metaphysics and not of science.
(Note that I feel that there may be a case for ID to be taught in US schools – but as philosophy, not as science. I was delighted to hear Robert T. Miller, in his criticism of Intelligent Design, advance the same argument!)
But before those against Intelligent Design leap too willingly in support of Popper’s milestone, we must be clear that it cuts both ways. There are many things currently discussed as science which are not testable (and hence not falsifiable) and as such must be considered metaphysics by Popper’s criteria. I would go so far to suggest that the very reason that Intelligent Design has been proposed at all is because careless scientists with no understanding of philosophy have been gradually trespassing on religions home turf (metaphysics and ethics) and claiming to have universally True answers. But there are no universally True answers in metaphysics! Metaphysics is always a matter of belief.
Nowhere is this more apparent than in the
dozens of quantum interpretations that now exist. These include the Copenhagen
interpretation, which claims that the waveform collapses at random; the Bohm
interpretation, which posits a non-local universal waveform that allows distant
particles to interact instantaneously; the Transactional interpretation, which
views interactions as the product of dual waveforms moving both backwards and
forwards in time; the “Observer Created Reality” (OCR) interpretation beloved
by mystics, whereby the conscious observer is responsible for the collapse of
the waveform; and the Many Worlds interpretation (or MWI) beloved by science
fiction writers, which attempts to resurrect determinism by positing the
existence of multiple “branching timelines” during waveform collapse.
Now we are free to interpret quantum mechanics however we wish, but the various quantum interpretations provide no means of distinguishing themselves from each other, and are not falsifiable in any demonstrable way. I shall focus on the Many Worlds interpretation, but it should be understood that the criticisms of this are equally applicable to any of the quantum interpretations.
It is presumably immediately clear why Popper’s milestone places MWI in metaphysics – the very formulation of this interpretation postulates mutually unobservable branching histories. Since these branching histories are not observable, they are not testable, can never be falsified and therefore lie clearly inside metaphysics. Hugh Everett, who formulated the original relative state model that gave rise to MWI claimed that it was falsifiable because any observation that falsified quantum mechanics would also falsify MWI. It is not at all clear why he believed that such a vacant tautology would be sufficient justification, since any interpretation of quantum mechanics can make the same claim.
The Israeli physicist Asher Peres was one
of many outspoken critics of MWI, most notably in his book Everett’s
Interpretation and Other Bizarre Theories. He questioned whether MWI was
really an “interpretation”, and even asked (not unjustifiably!) whether
quantum interpretations were needed at all. For science and technology, the
interpretations add nothing whatsoever to the body of knowledge. All they add
is a metaphysical component, and as such we are all free to choose which
quantum interpretation we wish and incorporate it into our belief
What of the suggestion that at some future point we might, for instance, be able to travel between the different timelines suggested by MWI, as happens so frequently in science fiction? Well, even if this speculation were later to be instantiated, this would not rescue MWI from being metaphysics now. After all, certain religious figures claim that at some future point God will reveal itself to mankind directly – but we're not going to let God out of metaphysics, and equally we should not be deceived into believing that MWI is anything other than a metaphysical belief.
Neither are quantum interpretations the
only metaphysical entities lurking inside science. In physics, we must also
accept that a great many astrophysical cosmologies provide no testable
basis. In biology, we need to recognise that the majority of teleological
claims cannot be tested – as Stephen J. Gould observed, we cannot know what
aspects of an organism conferred a selective advantage and what is a random
artefact of evolution. In chemistry, the periodic table has a metaphysical
component because its arrangement is partially subjective and cannot be tested.
(Note that this does not invalidate the periodic table, which after all is
simply a means of teaching chemistry, it just means that no-one can point to a
single periodic table and claim “this is the real periodic table”).
There is, was, and always will be a vibrant exchange of ideas between science and metaphysics, whether or not we agree to enforce Popper’s milestone. We are free to adopt whatever metaphysics we wish to inspire and guide our scientific investigations, but if we wish to use Popper’s criteria as a boundary condition for science we have an obligation to distinguish between that which is testable and that which is metaphysical. We should not be shy of this obligation, as it allows us to significantly clarify our thinking on a great many different topics.
Alternatively, we can reject Popper’s
solution, which in any case can only work if we mutually agree to uphold it, leaving
us facing Feyerabend’s position that there are no lasting boundary conditions
to science (or indeed to any human endeavour), in which case the whole
Intelligent Design debacle becomes a debate between people with
different metaphysical frameworks, with little hope of resolution. The fact
that one side of the debate rejects the scientific status of the other is of
little consequence, because without a boundary condition to assert there is no
way to say what “is science” and what “is not”.
I prefer to follow Popper’s suggestion, as it not only keeps religion out of science, but it keeps science out of religion. If we keep these two domains of human experience separate, we will be in a significantly better position to understand the universe through the exploratory mechanisms of science, carefully delineated from metaphysics of all kinds, as well as being able to foster a more tolerant and progressive society in which we acknowledge people’s absolute right to hold different metaphysical viewpoints without feeling the need to attack people’s beliefs solely for being different from our own. It remains to be seen if such a state of affairs can be achieved.
The opening image is Quid Pro Quo, by Gary Pruner, which I found here. As ever, no copyright infringement is implied and I will take the image down if asked.