Doing what works
Doing what works is one of the core principles of solution-focused practice. Doing what works means that when you try to accomplish something you pay careful attention to what is working, or has worked before in a comparable situation, and do more of that. Another aspect of doing what works which most solution-focused practitioners adhere to is 'If it ain't broken, don't fix it' which means something like, 'If something seems to be working well enough, there is no need to change it.'
Doing what works is more important than understanding why it works
Many coaching and therapy approaches place much weight on helping their clients understand what is happening in their lives, why these things are happening and what they need to do. In solution-focused change understanding plays a more modest role. The focus is on creating a vivid picture of what clients want to achieve and finding out what works to move in that direction. Doing what works is essential. Understanding why something works is seen as much less important. Is this surprising? Maybe, but look at this.
An evolutionary view on doing what works
Philosopher Daniel Dennett explains how comprehension is often not a prerequisite for competence. In nature, comprehension is not the cause of competence but the effect. Natural selection, over many generations, shapes characteristics into organisms which makes them competent without them realizing exactly why they are competent. There is no evolutionary advantage to shape understanding into the organism of why the characteristic is so beneficial; the characteristic itself is enough. "Your butterfly that has eye spots on its wings does not have to understand why this is a good thing for it to have. It scares off the birds but it is none the wiser." Does this principle only apply to organisms? No, it also can apply to artifacts made by organisms. Of course, comprehension can precede competence. Dennett gives the example of the Catalan Spanish architect Gaudi who was extremely competent and knew exactly what his cathedral should like before the first stone was laid. But individual termites, in nature, mindlessly perform some simple tendencies that were shaped into them by evolution and, together, manage to build something amazingly similar. A nice example of competence without comprehension which Dennett gives, is how Polynesian boats are developed and improved "Every boat is copied from another boat ... it is the sea itself who fashions the boats, choosing those which function and destroying the others." "If it comes home ... copy it! That's natural selection."
No focus on understanding problem causes
One of the types of understanding which is generally considered to be of little use in the solution-focused approach is understanding of problem causes. While solution-focused practitioners do acknowledge problems and don't scare away from talking about problems at all, they do no investigate why problems happen, how they evolved and what caused them in the first place. The solution-focused approach assumes that (1) understanding why a problem evolved is not likely to be very useful for building solutions because it is unlikely that from your understanding about what caused a problem will follow knowledge about what to do instead. Also, (2) analyzing why and how problems have evolved may elicit negative emotions in people such as defensiveness, hopelessness, anger and a feeling of being misunderstood which may prevent people from becoming creative and from thinking in term of possibilities.
No focus on explanations in terms of personal characteristics
Focusing on what works is focusing on process. It is focusing on what people have done that worked for them in specific circumstances. It is very situational and allows for a very dynamic view on people. An assumption in solution-focused change is that it is not useful or necessary to label people ("You are a typical introvert"). Also, solution-focused practitioners are very reluctant to think in terms of mental entities which cause behavior ("What are your basic strengths?"). The point is not per se to state that behavior causing mental agents or entities are non-existent but rather that there is no need in specific situations to try to understand and label these. The solution-focused process shows that it is perfectly possible to help people find solutions and make progress in a desired direction without labeling them, and without focusing on mental constructs. The work by Carol Dweck has shown that giving compliments focused on assumed strengths like intelligence can even be quite harmful.
No focus on taxonomies and questionnaires
Many traditional coaching and therapy approaches rely rather strongly on standardization by developing and using taxonomies and questionnaires. For instance, many positive psychologists use standardized questionnaires to assess signature strengths of people. Because the solution-focused approach assumes that focusing on mentalistic explanations is an unnecessary and even potentially harmful detour there is also no need to use taxonomies. The solution-focused approach relies on an idiosyncratic approach in which there is no need for standard labels and constructs. Instead, each case is viewed as unique.
Also read: Assumptions In Solution-Focused Change