The greatness and uniqueness of 'Image of the Fendahl' is shown in the scene where the Doctor "explains" what's going on to Adam Colby. Of course, he doesn't actually do any such thing. He suggests two possible explanations. He favours the first but his listener is sceptical so the Doctor offers an alternative which his listener finds more plausible. The Doctor also says that it might all be a coincidence. His tone is flippant but there is no real reason to suppose that he isn't being serious. It is clear that the Doctor is theorising and that he doesn't have the final answer.
This is fascinating and, as far as I can recall, unique in classic Doctor Who.
The Doctor has often been seen to behave superficially like a scientist (mucking about with test tubes, talking about oscillators, etc.) but this is the first and only real occasion when he really acts like one (like an idealised, Baconian one, that is). The Doctor is admitting that he doesn’t know and doing his best to come up with workable explanations which fit the facts. Moreover, the person the Doctor is speaking to is a scientist who has demanded answers and is coming to his own conclusions about how plausible the Doctor's ideas are. No final decision is reached or stated as to which solution (if any) is correct. Fendleman's rant to Stael before his death tends to support the Doctor's idea about genetic manipulation (Colby's preferred option, possibly because he heard Fendleman speak) but the Doctor seems to prefer his first idea about a "biological transmutation field" which Colby might doubt simply because he doesn't know what one is.
This is all highly appropriate in a story that is preoccupied with the tensions between science, evidence, theory, supposition, superstition and belief.
The story opens with Colby fretting over a dissonance between established scientific facts (the age of the skull) and the apparent impossibility of their implications. (Someone once asked J.B.S. Haldane if any scientific finding could disprove evolution; "Fossil rabbits in the pre-Cambrian" was his gruff response.) Meanwhile, Fendleman spends much of the story trying to convince Adam of the validity of his theories. Wonderfully, Fendleman gets it partly right and partly wrong (something else that doesn’t usually happen in tales like this). His theory about the pentagram being a neural relay seems to be borne out, but his idea of the nature of the power it contains is woefully mistaken. Nobody is really entirely Right or Wrong about anything in this story, which is very refreshing.
Stael is an interesting character. His employment of the occult ritual is self-consciously ironic and cynical. He rejects Colby's taunts about being a Satanist and claims to be unimpressed by "the grimoires". Nevertheless, he employs occult language and ceremonies... this might be meant as showing unconscious drives. Scott Fredericks (an actor with a lot of interiority) even seems to be working to endow Stael with a repressed sexual interest in Colby. Stael's ideas exist on that deeply-70s line of thinking along which the occult, paranormal phenomena and science intersect. This might be dated but it is perfectly appropriate with this story.
The story does a lot of that Nigel Kneale stuff. Apparently supernatural effects are revealed as side-effects of natural phenomena. Quatermass is usually mentioned but the story’s real debt is to Kneale’s masterpiece The Stone Tape, in which a team of practical scientists (!) who dig down in an old priory (!) discover that a haunting in the house is a kind of natural recording. The central female character in The Stone Tape has an unusual sympathy with the haunting/entity and ends up being absorbed by it… just like Thea Ransome. I don’t mean to accuse Boucher of plagiarism; there are as many differences as similarities and Boucher’s script, arguably, has more to say about the nature of belief that Kneale’s.
The Fendahl manifests itself in the manner of an all-out occult horror. Skulls, pentagrams, rituals, sacrifices. But the entity is clearly described as a horrible, one-off evolutionary snafu. It is suggested (the Doctor continues to offer suggestions rather than statements) that our human concepts of evil are influenced by the appearance and methods of the Fendahl... so human superstitions about evil come from our attempts to understand things like death and predation. The Fendahl is not stored inside a pentagram-embossed skull because it is diabolical, rather we have drawn our iconography of evil from a collective memory of the Fendahl, a creature so inimical to life that is it, effectively, a personification of death... but then, evolution is itself a kind of personification of death. It depends upon death as much as upon anything else.
Interestingly, the Fendahl never displays actual, conscious malice. I used to think that the core should have spoken up with sinister words. Watching the story now I am very glad that it stays silent and enigmatic. The closest it gets to expressing a malevolent personality is the little smile as it consumes human life force... but any creature might express satisfaction as it feeds. It is not really evil. It is just a supremely evolved predator. It is Death, in the sense that it feeds on living things in the most fundamental way possible: it assimilates them into itself... but in biological terms, that's quite right. To feed on something is to absorb those parts of it that can become part of you, excreting those bits that are unassimilable.
The key to understanding this story lies in the exchange between Ma Tyler and Jack about the nature of belief. “When most believe, that do make it true,” she asserts. “People used to think the world was flat,” Jack tells his grandma, “but it were still round.” “Ah,” she replies immediately, “but they behaved as though t’were flat!” This apparent gibberish is actually right to the point.
The story is full of people who behave as though their assumptions are correct and, in so doing, contribute to the situation in which the Fendahl reawakens. Fendleman and Stael, for their different reasons, have decided that the power within the skull should be released and so they set about it. Ted Moss clings to “the old ways” and thus takes part in Stael’s ceremony. Even Colby refuses to accept scientific facts when they contradict his assumptions and so brings Thea into contact with the skull. The Fendahl feeds on the life force, according to the Doctor, so it can be seen as a personification of death, more particularly as the dark side of evolution. But another subtext is also clear: it feeds on belief. Belief without reason. Belief against evidence.
How apt that it should have evolved as a result of natural selection turning back on itself.
The thing unfolds like a nightmare. I mean that in the broad sense. The story is dreamlike. Its narrative logic is fairly strong (even the matter of who releases the Doctor is fathomable, given some deduction) but the nuts and bolts of the story are jumpy, dream-logical, figurative and alliterative. The Doctor and Leela disappear into time for a brief period but return after what looks like a full day has passed for the other characters. We are asked to interpret quite important parts of the action from the standpoint of thematic rhymes and resonances. The fourth wall is broken. Spoken numbers fail to match the number of fingers being held up. We keep getting references to dreams. And dream scenarios crop up: sudden, inexplicable imobility for example. People have names that seem oddly appropriate. "Thea Ransome" suggests sacrifice: she is the ransom paid to a theistic entity. Even Ted Moss clings like a slow growth. The idiosyncratic editing emphasizes the peculiarity of the proceedings. We cut sharply away from scenes after highly pregnant remarks have been snapped out... and then the camera will linger longer than seems obviously necessary, in order to catch the expressions of a speaker or hearer.
The only cloud on the horizon (other than a certain painful tweeness in certain scenes) is the mooted notion that people might behave in certain specific ways because they've been genetically programmed to. But then, the Doctor only talks about "desires and instincts", which probably do have a genetic factor. Fendleman's interpretation is more extreme, and sounds like genetic destiny... but the Fendahl might've employed a scattershot effect, feeding in the right "desires and instincts" and hoping that eventually someone would be in a position to act upon them in the right way. Does it "explain the dark side of man's nature"? Well, if the Fendahl personifies evolution (through death and predation) then... maybe... but I don't think anything in the story reduces the picture to genetic-determinism.
Of course, either way, the meaning of the oblique title becomes clear. As does the significance of the name Adam. Whether it personifies brutal evolution or a demonic puppetmaster that depends upon unreason, the Fendahl, it is implied, created us in its own image.