– Infinity?
In: Mathematics
There are two main “types” of infinity (that have a lot to do with each other, but can be looked at out of context, I think), I’ll try to put them here:
1. “Development over time”: Let’s say you have a drink. Every five minutes you drink half of what’s remaining of your drink. Over time, the amount of fluid in your glass gets smaller and smaller, but you would never finish your drink. However, we know that, if we want you to be arbitrarily close to finishing your drink, we just have to wait some time, we can conclude that, **as time goes on**, the drink is finished (if we care to wait infinitely long).Another example would be: You have a big, BIG and strechable elastic red rubber band with a blue point on it, and a snail on that band. The snail moves with 5cm/h and every hour you strech the band by 1m. No matter how long the gummi band is, the snail will eventually reach the blue point (if it’s after 1m in the unstreched state it takes around 20k years, but snails live that long, right?).The important thing here is the development over time. That’s why you would often hear “as time goes to infinity”, that just means that we want to study the development over time.
2. “Big-ness of a set”: You want to know how big a set is. If you have finitely many elements in it, you can just count all of them and hurray. However, you can easily grasp that the natural numbers {0, 1, 2, …} are infinitely many (if they were finite, there would be a biggest integer k, but k+1 is also an integer that is bigger than k).If you now take any set and if you are able to “arrange” everything in the set in a way that you can count them (take {a, b, …, z, aa, ab, … , zz, aaa, …}) and are able to say: “a is my first element”, “b is my second element”, “aa is my 27th element”, etc. then you can say: “I can count this set”. This implies the question: “Are there sets that you can NOT count?”, to which the answer is yes, there are, for example the real numbers (without proof here, look up Cantor’s diagonal argument).Order theory in mathematics imply that you may have more, bigger “infinities”, however going there would go a bit too far.
Edit: To add, there is a mathematically sharp definition of infinity (Dedekind), however to understand it you would have to know a bit about functions, and even proving that you can compare any two sets as to which one is bigger is quite a bit of work (a good page of math)
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