Ehhh, I disagree. Quantities of physical things (like the number of oranges in a bag) are actual definite facts about the universe. Since we all agree that two follows one and that two plus two equals four, the ability to count gives us the closest thing to universally compelling truth we can possibly have. All of science and mathematics can be expressed as complicated ways of counting. You might make mistakes in counting, but the probability of this can be calculated in order to give what's called the 'statistical significance' of a result.
For maths see:
http://en.wikipedia.org/wiki/Peano_arithmetic#Arithmetic
The book, Gödel, Escher, Bach: an Eternal Golden Braid by Douglas Hofstadter explains this well.
For science:
http://en.wikipedia.org/wiki/Bayesian_probability#Scientific_method