Well, i don't know...
Some things are quite reasonable in quantum mechanics (although a lot of it is incomprehensible). For example, the indeterminancy of the true position and velocity of any particle. Whenever you measure something, you affect its position and/or speed by a completely miniscule amount. For example, when measuring the temperature of a hot cup of tea, some of the tea's heat must be transferred to the thermometer in order for you to record its temperature, thereby decreasing the tea's temperature and giving you a measurement just under the tea's actual temperature when you measured it. For macroscopic entities (things on our scale), this is not much of a problem as this does not cause much error at all. However, when you have a particle and want to measure, lets say its position, you have to bounce some small particles or waves off of it and record how long it takes to bounce back. However, due to the particle's small mass, just by measuring it you would have changed its course and it will now be moving at an unknown speed at an unknown position (you can, at any given time, either know its velocity or position exactly, but not both).
Science may seem incomprehensible at times, but things certainly are not just guessed (although sometimes luck has something to do with it- e.g penicillin). You just need to learn the background knowledge and build up your understanding step by step, thats all, and all will become clear(er).


"I have great faith in fools; self-confidence my friends call it."
-Edgar Allan Poe