Not All Truth Is Created Equal

Most people, whether on a day-to-day basis or in the grand scheme of things, are searching for some form of truth. That could range from the mundane (why do chicken nuggets exist?) to the profound (why are we here?). Regardless of the scope of one’s questions, some methods of working through those questions lead us to answers that are superficially plausible but actually incorrect. Let’s refer to these answers as PBI (plausible but incorrect).


PBI conclusions can be incredibly dangerous: the semblance of truth pulls us in and causes us to expend time, money, and other resources, only to have us discover we were wrong all along. So, today, we’re going to examine whether certain forms of reasoning lead to “truer” conclusions than others.

First, we’ll look at working backwards, in which someone finds observations and examples that support a predetermined conclusion. This method of thinking leads to a lot of PBI answers because you arrive at a conclusion and then seek to support it with whatever evidence you can find. By working backwards, one can open themselves up to numerous biases, including the availability heuristic, confirmation bias, and the predictable-world bias:

  1. The availability heuristic causes the reasoner to depend primarily upon information that is readily available. It’s intellectually easier to rely on information that is readily accessible to you, rather than acquiring new knowledge in order to make a decision. For example, in surveys, when people are asked to estimate the percentage of people who died from various causes, most respondents would choose the causes that have been most prevalent in the media such as terrorism, homicide, and plane crashes rather than more prevalent, “less accessible” causes like disease and traffic accidents that have less media play.
  2. The confirmation bias inclines people to seek evidence consistent with their hypotheses and then weight that evidence as more important than evidence to the contrary. For example, if you believe that smoking doesn’t cause cancer, you’ll search for points that support your claim and find ways to rationalize away opposing claims.
  3. The predictable-world bias revolves around our inclination to see patterns where they might not exist. This tends to occur in gambling quite frequently. Many gamblers believe in streaks of luck and often think they can see predictable patterns in game outcomes; however, the outcomes of these games are difficult to predict and highly complex in nature. Despite the complexity of reality, in general, people tend to grasp onto a simplistic sense of order to explain or justify their beliefs.

Based on these cognitive biases, it can be difficult for someone working backwards to maintain truth throughout their evidence and conclusion. If the conclusion is flawed from the outset, their evidence will also be flawed. Even if one tries to use statistical techniques to validate their evidence, they might rationalize by saying that they jut haven’t found evidence that points to their conclusion yet, rather than scrapping the conclusion altogether.

punctured truth

On the other hand, working from first principles makes it far harder to land on PBI conclusions. A first principle, by definition, is a self-evident foundational proposition that cannot be deduced from any other proposition or assumption. In short, what is something that we know to be irrefutably true? How can we build something up from there by adding more truths?

One of the best examples of reasoning from first principles comes from Elon Musk, who is notoriously reliant on this method of thinking:

“Somebody could say, ‘Battery packs are really expensive and that’s just the way they will always be… Historically, it has cost $600 per kilowatt hour. It’s not going to be much better than that in the future.’ With first principles, you say, ‘What are the material constituents of the batteries? What is the stock market value of the material constituents?’ It’s got cobalt, nickel, aluminum, carbon, some polymers for separation and a seal can. Break that down on a material basis and say, ‘If we bought that on the London Metal Exchange what would each of those things cost?’ It’s like $80 per kilowatt hour. So clearly you just need to think of clever ways to take those materials and combine them into the shape of a battery cell and you can have batteries that are much, much cheaper than anyone realizes.’

Instead of working backwards from a presumed truth, it behooves us to think forwards from the smallest unbreakable truth we can find. When using first principles, you can find a way to make rockets so cheap that a business, rather than a government, can build them. You can elegantly prescribe a medication for heart disease (common aspirin worked about as well as name-brand Vioxx, which also had the nasty side effect of death sometimes). While first principles require huge amounts of research and intellectual rigor, they will often land you closer to a real truth than working backwards will.

SpaceX Costs

Also published on Medium.

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