You only believe in something when you don’t know.
Update: So you build a machine according to an interpretation of data and you design it so that when A is done P is the result.
You believe A will produce P. You hope A will produce P.
So you action the apparatus but it produces X instead. Now you know that your belief that A produces P is false.
However if you continue believing A produces P, when I know it doesn’t because experience shows it doesn’t, then we will disagree.
Your problem then is rejecting experience and replacing it with hope or belief. This is the working of the religious mind which believes in the absence of fact or knowledge. Religious minds believe belief always trumps reality.