Final answer:
Expert witnesses are professionals or individuals respected in their field who provide evidence and viewpoints based on their expertise or authority. They are essential in trials to explain things outside the common body of knowledge.
Step-by-step explanation:
Expert witnesses are needed in a trial to explain something to the judge or jury that is outside the common body of knowledge. This is included in the concept of testimonial knowledge.
Expert witnesses are professionals or individuals respected in their field who provide evidence and viewpoints based on their expertise or authority.
The testimony of an expert witness is given weight and consideration because they have specialized knowledge beyond what is commonly known.