Faith plays no part, it is based on observations and formal proofs.
Nature itself is indeterminable to 100% accuracy, so technically everything can never be stated with absolute certainty, only at say an exceedingly high probability it in a practical sense might as well be true, eg the temperature right now is 21.3ºC, but not exactly etc.
Correct depth perception, when doing enough sums, can pick up where others haven't carried properly etc, but your gene pool opinion: Religion did that!
