Sherlock Holmes uses deductive reasoning to solve his cases. What is deductive reasoning? How does it differ from guessing? What knowledge and skills does it require? Using examples from the story, describe how Sherlock Holmes uses his scientific method t

Deductive reasoning is a top-down approach to come up with a premise (statement or claim) that would justify a conclusion. On a particular scenario, the investigator first gather all the evidences then work on it by reasoning (if that particular information is helpful or not in a case)- narrowing the range down until there's only one premise left. Contrarywise, guessing is simply approximating or gauging something with no sufficient information and the opposite of sound & well reasoned statement. Should any investigator uses guessing as a tool to solve a crime/case, it would be more likely a missed than hit deal for them.

Sherlock Holmes is a very brilliant detective that observes countless details about the scene and the victim that many of which the police seem to have overlooked, then from that information arrives at a conclusion that is not necessarily true, but is probable based on the information available. Sherlock actually starts from a clean slate with no existing information for comparisson on every case.

He literally snoops to get sufficient data through keen observation & interviewing people, on a clean slate (no previously acquired information and no suspect in mind). Holmes once stated, "...how dangerous it always is to reason from insufficient data". "It is a capital mistake to theorize before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts."

For example, the victim went missing for days and was found dead on a cabin. He would walk in the crime scene with no previous data to compare and no suspect in mind, simply would snoop around to collect information. Perhaps the victim died out of a natural cause; suicide or probably a foul play- murdered. There’s the glass from a broken window, but this might have already been broken when he arrived, or it may have been broken in a struggle. Does he have lacerations? Is his clothes damp from the rain outside or dry? Does he have an existing health condition? And he will continue to answer his "what ifs" and look at every angle of the scene to get enough information. He sorts and scrutinizes every detail at hand to come up with a premise that justify his conclusion.