Reevaluating the Slogan: The Pitfalls of 'Same Logic, Same Response’

It’s time we reconsider the slogan “same logic, same response”. Currently, it struggles to effectively communicate what I aim to express. When taken literally, albeit with necessary qualifications, the slogan is misleading. I fear an overreliance on numerous caveats might lead to ad hoc justifications, which is not ideal. Let's delve into this.

The statement is inaccurate when interpreted literally, as logic alone doesn’t encapsulate the entirety of an argument's quality. An argument can be logical yet still flawed due to its false premises. Consider a frivolous example: "All logicians are unicorns. Patrick is a logician. Therefore, Patrick is a unicorn." This represents a valid argument, hence logically impeccable, but it's fundamentally flawed because the premise is untrue – no logician is a unicorn. Another argument with identical logical structure might be sound if its premises are true. For instance, “All humans are mortal. Patrick is a human. Therefore, Patrick is mortal.” Although these two arguments share the same logical framework, I don’t anticipate an identical response to both. I hope to have not convinced you of my mythical status, but I can assure you, I am indeed mortal.

So, the first caveat: by "the same response", I refer to an identical logical evaluation. This means assessing whether the premises logically support the conclusion. Both cited examples are valid, and thus, from a logician’s perspective, they are equally logical. This pertains specifically to deductive reasoning, where the standards are centered around validity.

In non-deductive scenarios, additional caveats are required, as context influences logical support. Non-deductive contexts are marked by more flexible logical standards, focusing on argument strength rather than validity. The premises here do not fully guarantee the conclusion, allowing a margin for error, which varies according to the context. Take this example: "90% of Aucklanders are zombies. Patrick is an Aucklander. Therefore, Patrick is a zombie." What are the odds of Patrick being a zombie based solely on the given premises? 90%, seemingly. It’s a probable hypothesis, though not certain. However, if new information emerges – say, no zombies have yet reached Waiheke Island, and Patrick resides there – the likelihood of Patrick being a zombie drops significantly.

This leads to the need for another caveat in non-deductive contexts. My colleague proposed incorporating a 'ceteris paribus' clause, modifying the slogan to “same logic, same response, all else being equal.” What exactly needs to remain constant? As I’ve elaborated in "Logic in the Wild", this is a complex issue, which I invite you to explore further in the book for a comprehensive understanding of 'ceteris paribus logic'.

For the purposes of this post, we can simplify it to mean that the information surrounding the premises should remain equal. If the only information available is that within the premises, with no external data, we attain a greater degree of logical stability across various contexts, including in non-deductive reasoning.

An application of this principle can be seen in political discourse. For instance, when critiquing the Prime Minister's lack of what I term 'meta-coherence' (a concept for another post) in handling cigarettes and cannabis policies, this principle comes into play. If the rationale for not reducing cigarette sale outlets is to avoid a black market, a similar logical approach should apply to cannabis, ceteris paribus. However, as expected, counterarguments often highlight dissimilarities in context, as exemplified by Luxon's “different story, different effects” response.

Hence, the second caveat: the context of evaluation must remain equal. Of course, one might argue, as Luxon did, that the contexts are not equal. This illustrates the need for further caveats, potentially leading to an unwieldy number of ad hoc qualifications for the "same logic, same response" slogan.

I'll leave the discussion here for now, intending to revisit and potentially reformulate this slogan in a future post. There’s much more to unpack, but for now, I must attend to other matters.