The future is always an idea. The past has come and gone but we can look at historical data and compare it to those in the present. In these situations assumptions need not be required.
However there is a science-based faith and that is when we must rely on the preponderance of the evidence &/or beyond a reasonable doubt. Yes ... these standards are applied in court but even in science we rarely have all the evidence. We must extrapolate from the data to the more general case using one of the two principles. Statistics also play a role in the process of science such as in quantum mechanics were classical causality has been superseded by probability. The computer I write on is based on quantum mechanics but it works.
Any belief consists of our minds filling in the blanks between things known and unknown.
However faith in science isn't to be confused with religious faith where often there isn't any evidence to speak of and sometimes the laws of everyday physics were seemingly suspended
, e.g. Jesus walked on water. In religious faith emotionalism trumps skepticism.