Conjecture: One can try to disagree with just a key part of Popper’s philosophy (like his take on the line of demarcation, or the paradox of tolerance or what democracy actually is) – and attempt to embrace the rest, but then one finds inconsistencies in their own thinking. It becomes clear to a casual reader that if I reject this key part of Popper's philosophy, then (logically) that entails rejecting that part and then that part and that part and so on. Soon I have to reject it all.
 
And I must reject it all if I reject some key part (like authoritative sources, or a critical method) because to do otherwise would be to change my worldview and thus so much of the received wisdom I have been taught or indoctrinated with. So I have a choice: embrace the change and indeed change the way I think about almost everything in my intellectual life (and even about what I regard as common sense) – and this might be painful (in truth, to a Popperian, it’s fun – or it can be learned to be fun).

Or I can simply reject Popper.
 
Embracing the critical rationalist worldview/Popperian-style philosophy is deeply psychologically destabilising at first. It means viewing reality in a new way and thus removing oneself, in a sense, from one’s intellectual peers. Popper is not like other philosophers. I can reject elements of Descartes (let’s say his “proof” of the existence of God) – but accept his cogito (“I think therefore I am”) and feel no great destabilisation in my thinking. Leibnitz’s “monadology” whether I embrace or reject it, would seem to have no great bearing upon how I think deeply about each and every issue. Perhaps there is a fundamental indivisible particle. Perhaps not. Perhaps there is an intelligent creator. Perhaps not. Much of this is disconnected, to some extent, from the problems I am interested in my life anyway.
 
But Popper and Deutsch change (and challenge!) my actual thinking – moment to moment. And on topics near to me. I cannot be sure of anything – but I know quite a lot. I can improve my thinking and myself. I can make progress. I am self reliant, but I can cooperate. There is no authority I need to turn to, but I can criticise any who claim to be a source of truth and thereby come closer to the truth myself. No one has the final answer (including me) and “we are all equal in our infinite ignorance”. And that last one can give one a real sense of vertigo upon first really comprehending it. And not all people find vertigo - that sense of falling - fun. But we can all learn to. Yet few people, as a proportion of the whole, ever choose to go skydiving despite the recommendations of almost everyone who has.
 
Philosophy - and Popperian philosophy in particular - goes right to the deepest parts of one's psychology and how they frame their thinking on any topic worth thinking about. It requires a shift in gears, which many (not all!) find unpleasant - at least at first. Like skydiving or roller coaster riding. Should the unpopularity of any fun thing count against it? Of course not. Most people simply do not know what they don't know. It does not count against skydiving that it's unpopular. Nor anything else people find gives richness and purpose to their lives but which is poorly subscribed.

​And if one has spent a career defending a mainstream thesis, or a thesis that has merely adapted some ideas within a mainstream framework, it is unsurprising then, that one would be reluctant to relinquish all that framing for fear of the mental pain and anguish which might accompany it.
 
Unless, of course, that person is truly, to their core, a Popperian. In which case that kind of relinquishing is one of the most joyful parts of life.

This review is really for people who have already seen the documentary. It does not try to explain how intriguing and interesting the documentary is but does refer to some of the content of the documentary. There are no significant spoilers (but there are some - marked).
 
Who knows how accurate this documentary is, unless you are one of the people actually involved in the case, who went to the hearings and got to hear arguments about all the evidence from both sides? I only watched the 20 episodes of this show, so I don’t know. I do know documentary makers can make stuff up or emphasise the wrong thing and completely eliminate important information. Anyone who enjoys science documentaries knows this. Especially animal documentaries. If you’ve ever seen an episode of “Meerkat Manor” you will know what I mean. The narrative and anthropomorphising is so cartoonish, one would barely have been surprised had the little critters’ noises been subtitled in English. That aside, documentaries about people are often so interesting because we can get an insight into how people think given what they say. And this documentary underlines what many of us thought we knew about how legal minds sometimes tend to think. From judges to lawyers, police and even family members of the victims and accused -  how people think about evidence can be astonishing – and frightening. Because people’s lives hang in the balance on these questions about evidence and its use in courts of law – apparently - at times. 
 
So there are two epistemological challenges here: (1) to what extent we can know the documentary is accurate in terms of its couching of the events from beginning to end of the trials (2) taking at face value what the people involved say and do about “evidence”.
 
Rather often the language used by – and indeed the expectations of - the professionals involved – is about what the evidence “points to” and how the “balance of probabilities suggests that” and how it might be “easy for someone to believe” and so on and so forth. The evidence is supposed to speak for itself in some way and if a plausible story is told that fits some of the evidence, then this means that the story is in some way “credible”. 
 
But given any set of facts (“the evidence”) an infinite number of stories can always be told that are “consistent” with it. Consistent does not mean much when it comes to evidence and explanations – it just means “not contradicted by”. For example – from my first to last waking moment, everything I experience is consistent with my being the only actual person in the universe. Or that I am still dreaming. Or that I just came into existence and that at any moment…NOW…I might be gone again. These are all terrible explanations. Yet consistent with “the evidence”. A dent in a car can be evidence the owner crashed it. Or someone borrowed it and crashed it. Or someone stole it and crashed it. Or no one did anything and the brakes failed while it was parked on an incline. Or a passing ruffian with a baseball bat (or strong kick) dented it. Or a meteor fell from space. Or…the list of “evidence” and theories “consistent with it” is literally infinite. As we will come to see whether any of those theories are good explanations of the evidence comes down not to consistency (which is just an entirely insufficient logical necessity) but whether any evidence actively rules out a good explanation in the case where we have two (or more). In most cases we are lucky to have one explanation. In some very rare cases there are two good explanations – and in that case, that’s where the role of “crucial” evidence comes in. We shall come to this, and its role in the documentary, momentarily.
 
In courts of law we have a problem scientists have not always understood but which some philosophers have – that of “the evidence” being interpreted. Evidence is theory laden. It does not speak for itself. Nowhere is this more profoundly revealed than in this documentary series. [Minor spoiler alert]. I will give an example: it is asserted by the prosecution that the murder victim was killed by a bullet to the head. She was shot, in the head whilst in a particular garage – owned by the defendant. This is all seems very compelling and under almost all other circumstances similar – it might very well be the only purported explanation. And it might well be reasonable.
 
The bullet, we are shown, is provided to the court and an expert witness brought forward to say the bullet, fired from a gun owned by the defendant had been analysed and the victim’s DNA found upon it. Again: that seems to be terribly compelling evidence. The accused shot the victim in his garage with his gun and the bullet was left behind after it passed through the victim’s skull. It is – as they say - “consistent with” the defendant firing the gun through the head of the victim. But is it the best explanation? What other explanations could there be? Well in this case there was another good explanation: the entire police force involved and prosecution team were equal parts incompetent and corrupt and some of them framed the defendant. Why is that ever a good explanation? It rarely is, except that in this case the prosecution – the state – had motive and means. The state was in another legal battle at the exact time the murder purportedly occurred – and not against just anyone. But against the defendant for *wrongful conviction* for a rape years earlier and the defendant was seeking legal damages into the millions. These are high stakes. But how can we distinguish between these two cases – the defendant is the killer or the defendant is being set up?
 
It should be clear we cannot look for stories consistent with the evidence, or evidence that “confirms” a particular theory. We must, and solely, in this rarest of situations - look for evidence that can categorically rule out a particular theory. Indeed this must always be the defence team’s purpose. To rule out their client…and if they cannot, then the best explanation (the case put forward by the prosecution) must surely carry the day. The defence, upon being successful, then leaves everyone in the unfortunate situation of saying "We don't know" - we do not know who committed the crime. And the police should redouble their efforts to construct a new, better theory that actually explains what happened.
 
But in this case there were many pieces of evidence ruling out the guilt of the defendant (as the documentary explained). For example, if the victim was indeed shot in the head in the garage – why was there no blood found anywhere? The evidence of a clean floor in all the places the victim was shot, and earlier apparently stabbed and raped – is crucial evidence against the theory either that gunshots and stab wounds reliably cause bleeding or that the victim was never shot or stabbed at that location. Many competing “what if…?” questions might be asked. What if they cleaned the floor? (With what and why is there no cleaning residue as expected and why is the rest of the garage still such a mess if it was cleaned?). Why do ballistics experts agree there should be blood splatter everywhere in the garage – especially microdroplets of spray? Why would they clean all the blood but not the bullet? 
 
Years later, when scanning tunnelling electron microscopy is used to image the bullet up close, there really is crucial evidence. The bullet – apparently used in a murder - when compared to other similar bullets fired through bone – shows no sign of bone residue. Yet all other similar bullets do and there is a good explanation of how bullets fired through bone, end up with bone fragments in them. Bullets get impaled with whatever material they pass through. And in this case the bullet in question, when compared to similar bullets fired through a plywood wall of the garage shows signs of plywood. This evidence rules out the theory it was fired through bone and the best explanation for its presence in the garage was that it was fired through the plywood wall of the garage. Indeed dozens of bullet holes in the garage and thousands of bullets fired on the property testify to the fact this bullet was not unusual at all in that garage. Except in one way: it was claimed to be a murder weapon lacking any evidence of being a murder weapon.
 
That plank in the case of the prosecution team collapses. So the bullet did not go through bone. It was not the murder weapon. And if that is what the evidence that was supposed to be explained by the defendant actually being a murderer, then the defendant is not a murderer. Very very few people are murderers. But people who are suing police forces for many millions of dollars might very well be accused of such. [Spoiler alert] For those reading along: the DNA of the victim found on the bullet is explained as being planted using a source from the victims’ home.
 
Now I do not know the truth of any of this. But what struck me watching it was how again and again the police evidence was simply put forth as being “consistent” with a particular story and this led to judges and others seeming to become more and more “confident” in that particular explanation. 
 
While on the other hand, evidence that ruled out the defendant was not held up as being of crucial importance. Crucial in two senses (1) it is of the highest importance. More important than other “circumstantial” evidence like “a bullet was found in the garage of the accused” and more significantly: (2) it categorically rules out one of the two competing good explanations.
 
It is rare in criminal cases to have many competing good explanations – just as it is in science. Very often when the police have identified a suspect, they have good reasons for doing so: there is a video of the crime. There is blood literally on the hands (or shirt) of the accused. There are many independent witnesses. All of this comes together to make a very hard to vary explanation of what happened. But in this case, the fact is, from what is shown in “Making a Murderer” at least two good explanations – both hard to vary (but to rather different extents) exist. And in this case it is the crucial evidence – the evidence that can decide between the two competing theories – that matters most. And in the documentary there is a long list that, to a typical viewer, shows the accused is innocent of the murder because the evidence was planted. 
 
 
To summarise this: the best explanation is: some evidence *consistent with* the claim “he is guilty of murder” was planted…and a bunch more evidence that rules out “he is guilty of murder” was utterly ignored.
 
I can heartily recommend this to everyone. Compelling viewing for anyone interested in epistemology and philosophy (as well as everyone else!).