Is there any rational way to defining mistake? Are mistakes always retrospective?
Why do we call them mistakes? When a child is learning to walk and falls, was it a mistake? When a toddler learn the meaning of hot by placing it's under on a hot plate, was it a mistake? People don't make mistakes. They learn. Some take longer than others or the "test" maybe more difficult, but it's still about learning. If one found a sharp saw, it would be a mistake to cut off one of one's arms or legs with it to test how chirp it was. There's a non-retrospective mistake.
But if mistake is unintentional then guilt and regret will loose their meaning, and mistake would become unavoidable. An error in judgment isn't always retrospective. People who make mistakes say they were unintentional, but I believe that is often a lie. When I make a mistake that deviates from having a positive impact on "the life," then I feel regret / guilt. That regret / guilt provides a force to get me to correct my ways and prevent committing the same mistake.
Humans preconceive mistakes then act on them all the time. Perhaps the outcome has a known probability of ending in a mistake. One type of this common behaviour is risk taking. Another activity with a probability of failure is practicing or performing a skill.
Often, the mistake might be expected. One may perform a scientific experiment and receive a null result. In these cases, one may simply be amassing evidence which increases knowledge. Making mistakes is a vital method for understanding objective reality. The importance of this human nature is supported by the cliche status of, "We learn from out mistakes."
However, from an holistic perspective, one can reasonably argue that no consciously chosen behaviour can be considered a mistake as long as one has considered the risk or other purpose for embarking on a task which could end in failure, in the first place. From this line of reasoning one can say that the determination of the mistake is only possible in hindsight.
If the decision being made with available knowledge which is thought to be correct results in a consequence that was not intended, then I call that a mistake. Choosing to act otherwise, while knowing the right decision, is intentional, and I consider that to be worse than a mistake. I call that wrong judgment, unrighteous judgment, or corrupt judgment. If people ignore unintentional consequences and don't call that a mistake, then they have negative effects on others and society without thinking that is wrong.
Can it be said that with the available knowledge and resource, if a decision is taken which you think it is logically right, then no matter what outcome it leads, it wont be considered as a mistake? And if we know the right decision at that context but still choose to act otherwise ... it will be a mistake, irrespective of the outcome.
Well, mistakes aren't always retrospective and in fact we are made to make mistakes as unrational beings.