Two goats. Two more. How many are there? Obviously four.
It seems simple, but you may not realize you've just made an incredible trip from:
1. Thinking about goats
2. To thinking about abstract numbers
3. Thinking about goats again
You made a round trip from the goatverse to the numberverse, and didn't break a sweat. Humans are among the few (or maybe only?) things capable of making this trip, and we benefit from it enormously.
We can do arithmetic on goats, oats, moats, and boats, and never even realize that we're warping into an entirely different universe each time - one without goats, or ANYTHING physical at all. Just abstract numbers.