If you’ve ever seen a police or detective drama, you’ve no doubt heard terms bandied about to classify types of evidence. “Don’t worry about it Johnson,” the gruff detective will grunt to his subordinate. “The evidence is purely circumstantial.” In reality, evidence being “purely circumstantial” is hardly derogatory.
Direct evidence is something that proves a fact without further discussion necessary. Circumstantial evidence, on the other hand, usually requires some sort of inference or logical step for any useful information to be gleaned. The difference can be clearly illustrated with an example. If someone witnesses reckless driving, then depending on the truth of his or her claim it can be treated as direct evidence. However, if that same person were to instead see a drunk person stagger into their car, hear a crash and bear witness to the carnage without seeing the crash or infringement itself, that’s circumstantial because they’ve had to make an inference of what happened.
Without a doubt, and against what popular media might have you believe, both are valid forms of evidence. Within cases where direct evidence is simply unavailable, as in the Scott Peterson murder case of 2003, circumstantial evidence and clear lines of reasoning are of paramount importance. Furthermore, this type of evidence can secure a conviction on its own. What must be kept well in mind though are its weaknesses.
Let’s return to the latter car crash example, where the witness missed how the crash took place and only saw the aftermath. When averting their gaze, it is possible they could have missed some crucial detail like a pit in the road or latent distraction that was the true cause for the crash. Similarly, the sound of a gun isn’t necessarily the reason for the body you’ve just discovered, although it might seem rational to believe that with a cursory examination of the scene. If you’ve ever performed this kind of inference on a less drastic scale, like for example having a bad experience at a restaurant and attributing that negativity to the restaurant itself rather than whatever was at play, you’re not alone. The tendency to make inferences despite there being insufficient evidence to do so accurately is ingrained in all of us.
“Caltech scientists have discovered that uncertainty in terms of the causal relationship” Scicasts Ltd reported in 2015, “is the main factor in determining whether or not rapid learning occurs.” In other words, we have a tendency to try and rapidly acquire answers to questions even if we lack the information to do so accurately.
So what if we were to assume that we are living a perfect world in which all-legal professionals can interpret circumstantial evidence to the truest extent? Even in such a world, the legal profession is faced with the nigh-on legendary problem of induction. This centuries-old problem is one mathematicians, philosophers and legal professionals still have not resolved. So what is it? It’s the cold fact that despite how much we rely on induction in every-day reasoning in addition to the interpretation of evidence in the courtroom, nobody can know for sure that past instances of a thing occurring necessarily guarantee that such behaviour will continue. We know the sun will rise in the morning because we’ve seen it do so before, yet that isn’t sufficient basis for believing it will continue to do so. Accountants and economists have known this for decades in the oft-repeated warning, ‘past performance isn’t a necessary indicator of future performance.’ In truth, there is no reasoning at all behind inference despite us calling it ‘inductive’ reasoning. It is merely a causal chain established through repeated observations of similar performance. Yet, we trust in it unfalteringly, just as the gambler might see previous winnings as a fallacious omen of future wealth.
Although the domains of wrongful death lawyers, contract lawyers or divorce lawyers may not necessarily face the same risk of evidence misinterpretation and inference, they can each apply the lessons from managing such risk to their professions. After all, the ability to carefully consider all sides of an argument, case and circumstances surrounding a legal problem in general without giving in to natural inclination is highly necessary within and without the legal profession. The truth is, although the process of inference and consequently the interpretation of circumstantial evidence might be flawed, we simply don’t have a choice sometimes. Returning to the Peterson case, there was no direct evidence to draw upon. The options, therefore, were to either let the murderer free or respect the circumstantial evidence and build as convincing and likely an interpretation as possible as a result. Yes, a probability isn’t perfect, but sometimes it’s the best thing available and it’s a risk the justice system and wider society is willing to take.
In summary, we can do a pretty good job with what is essentially just remembering observations about the world. When we see rain, we assume puddles will form because we’ve seen puddles form before in similar circumstances. Fortunately, we don’t always need to understand why something works to utilise it. All sciences feature a multitude of mysteries that are simply taken for granted without knowing their fullest extent. Similarly, as long as legal professionals are aware of the existential as well as logical risk associated with reliance on circumstantial evidence and therefore the problem of induction, they can take their judgements based upon it with a grain of salt.
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