If it's a well-established fact (a 'scientific fact') that we have 23 chromossomes, wouldn't it also be true that we have 22 chromossomes?
For example, I can have an orange in my hand and ask: What is true about this fruit?

If I'd say: "It's spheric", it would be considered an observable fact, therefore, truth.
If I'd say: "Its colour is orange", it would be considered an observable fact, therefore, truth.
If I'd say: "It's heavy", we might start to have different opinions. How much weight constitutes the quality of being "heavy"? What is a fact, therefore, truth, about it? The measurable fact is that this orange is 0,2 Kg. Some will interpret this fact as "heavy" and others will interpret it as "not heavy".
If I'd say: "It's sweet", then we start getting into really controversial territory. Sure, we can measure the quantity of sugar in it, the degree of acidity, etc etc. those are all measurable facts, but each person's palate and experience will be different. For some, it will be "sweet", for others it will be "acidic", etc etc.
So, at what point an observable fact generally accepted as "truth" may become subject to different, even opposing interpretations?
Eden