The Fermi Paradox: Are We The First?

This is a possible consequence of the “too rare” solution, that we may be the first ones to emerge in our galaxy, or even all of the Universe that we can observe. However, this solution only requires rarity before our emergence, and not after.

But considering when we emerged, it is hard to point to what might make our emergence rare before when we emerged and common afterward. An obvious possible limiting factor is metallicity, the abundance of elements heavier than hydrogen and helium, what astrophysicists call metals. Old and exploding stars have gradually been enriching the interstellar medium with metals, giving later-forming stars more and more of metals. However, Earth-sized exoplanets have been detected orbiting stars with a wide range of metallicities, sometimes much less than the Sun’s (An abundance of small exoplanets around stars with a wide range of metallicities | Nature). This makes it unlikely that the Solar System was the first planetary system with habitable planets.

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Fuzzy logic

Fuzzy logic is the addition of other sorts of values to true and false, like adding a “maybe true or false” value, and using a continuum of values between true and false. Traditional mathematical logic, with only true and false, is sometimes called crisp logic by comparison. It is also known as Boolean algebra, from 19th cy. mathematician George Boole, who found analogies between logic and arithmetic.

Fuzzy logic has turned out to be very useful for device control, because it is a good way of handling real-world conditions. For instance, when does gray stop being black and start being white? For crisp logic, one can say black – medium gray is dark and medium gray to white is light. That is not very informative, so we subdivide these ranges: black to dark gray is dark-dark, dark gray to medium gray is dark-light, medium gray to light gray is light-dark, and light gray to white is light-light. One can continue with these subdivisions, reinventing binary representations of numbers. But once one does that, one can use the numbers directly. Black is 100% dark and 0% light, dark gray 75% dark 25% light, medium gray 50% dark 50% light, light gray 25% dark 75% light, and white 0% dark 100% light. Once one has such numbers, one can then use them in fuzzy analogs of crisp-logic operations like “not”, “and” and “or”.

Below the fold, I will construct some a simple system of fuzzy logic using “maybe true or false”.

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