*And… The last Big Idea by our Elena Butti*

For the nicotine-lovers among you: how many cigarettes a week do you smoke?

If it’s just one a week, you’re definitely not a smoker. But what if it is two? Again, you’re not. And if it’s three, four, five…?

There is clearly a point at which you won’t be able to assert that you’re not a smoker any more. The question is: when does the passage from non-smoker to smoker take place?

This is a variant of the *Sorite paradox* (from the Ancient Greek *sòros*, which means “heap”), attributed to the Ancient Greek philosopher Eubulides of Miletus. His paradox followed this argument:

1 grain of sand does not make a heap. If 1 grain of sand does not make a heap, then 2 grains of sand do not make a heap. If 2 grains of sand do not make a heap, then 3 grains of sand do not make a heap. [and so on until…]If 999,999 grains of sand do not make a heap, then 1,000,000 grains of sand do not make a heap.

It’s like saying that smoking 1,000,000 cigarettes a week does not make you a smoker, because it is not substantially different from 999,999, which is not substantially different from 999,998, which is not substantially different from…1. There’s something wrong. But where is the mistake?

It really would not make sense to establish a precise minimum number of grains for them to constitute aheap. The problem is that heap is a *vague concept*. There is no clear definition of when something is or is not a heap, therefore making it very problematic to assess whether the statement “This assemblage of grains is a heap” is true or false.

Traditional logic is *bivalent*. It means that it only allows for a statement to be evaluated in two ways: either true or false. However, the intrinsic vagueness of many terms, for example “heap”, suggests that bivalency might be too rigid an approach. We need a more *complex* logic. It is called *fuzzy logic*.

Fuzzy logic is a concept first proposed by scientist LoftiZadeh. Rather than relying on binary true-or-false sets, fuzzy logic variables may have a truth value that ranges on a *continuum* from 0 to 1. For example, a statement can be 0.6 true and 0.4 false.

Fuzzy logic is now being applied to the technological field. While computers still work with a binary system (ever thought: “computers are stupid”?), the developing field of artificial intelligence relies on fuzzy logic to mirror the complexities of the human mind.

Post-structuralist anthropological and philosophical theories also make use of fuzzy logic in their attempt to deconstruct the binary categories of Lévi-Strauss’ structuralism (man-woman; heterosexual-homosexual, for example) and to recognise there is a whole grey area in between the two “extremes”.

This might seem way too abstract, but fuzzy logic is also highly relevant in your daily life. If you smoke, you know it’s bad, but you probably think (or hope): “one more won’t kill me”. And it is indeed likely that *that one more* cigarette will not.

In traditional logic, this would mean that *that one *cigarette *does not* kill you.

In fuzzy logic, it neither does, nor it doesn’t. It does(n’t) *a little bit*.