fishbulb

Random chance is a placeholder for what we cannot explain systematically or probabilistically. It may be the case that a behaviour appears to be random because, fundamentally, it is, or it may be the case that the behaviour is systematic, but we are unable to discern the rules governing it. There would be no way for us to tell the difference between the two, but the goal of the scientist would be to see if we could discover some sort of systemic law or rule to describe and predict that behaviour.

In either case, saying that something is random is not an explanation; it is a concession. When you say that a behaviour is truly random, you are saying that you cannot explain why it works the way it does, and you cannot predict which of the possible outcomes will happen. If I say that the toss of a coin is random, I am saying that I cannot explain why it came up heads rather than tails on a particular trial, and that I will be unable to predict whether it will come up heads or tails next time. Alternatively, I might suspect that the toss of a coin is not so random, and that by examining such things as the mechanical action by which the coin was flipped, local air currents and conditions, and so forth, I might be able to predict the outcome of each trial, if not with complete certainty at least better than random chance. I.e., be right more than 50% of the time, in this case. If, for argument's sake, the result of a coin flip was truly random, I could never explain why any particular trial worked the way it did; I would be limited to making statistical predictions of the aggregate outcome of groups of coin flips. In that case, the behaviour of individual elements cannot be explained, even though their aggregate behaviour can. (For example, we can predict the half life of a piece of radioactive material with very high accuracy, but we cannot predict which particular atoms are going to decay at which particular times.)

This is the whole point behind science: to explain why things happen they way they do so that we can predict with accuracy and consistency what will happen or what we will discover in the future. Saying that something is random marks the point at which you decide to stop doing science and accept that certain things cannot be explained.