Sherlock Holmes may be a rationalist, but his process is invisible to the reader.

A typical Holmes conversation (in form, at least):

Lestrade walks in.
SH: From your appearance, I can tell you just came from the morgue.
L: Gadzooks. You are correct. How did you know?
SH: I smell (some chemical) on your clothes. Also, the leather in your shoes is discolored as if (some other chemical) has dripped on it. The only places that use those two chemicals are (some ridiculous industrial location) and the morgue. Since you are a police officer, the logical conclusion is that you have just left the morgue.

But all Holmes' facts (except that Lestrade is a police officer) are invisible to the reader. Also invisible to the reader are the facts about Lestrade that are irrelevant to the story or the analysis (i.e. Lestrade was wearing a brown jacket, he recently shaved, and is carrying a note in his pocket, probably a list of items his wife wants him to buy on the way home).

Even if we wanted to, we couldn't follow along with Holmes' reasoning, including the dismissal of the irrelevant facts. In short, Holmes' "rationality" is really deus ex machina in favor of a character in a story.

There's another massively important step: Check for alternative hypotheses. It's easy to think of explanations for observations, but usually they can have multiple meanings.

Oh, and the painting I mentioned at the beginning? I actually didn't figure it out until she told me. I just about kicked myself when I realized I could have figured it out myself and pulled off a really cool Sherlock Summation if I hadn't asked first. C'est la vie.

Hindsight bias!

How to Draw Conclusions Like Sherlock Holmes

Engage slow motion mode and run an annotated physics simulation in your mind.

I have some magician/"psychic" friends, and so much of that is cold reading (which is pretty much what Sherlock does) and other Dark Arts.

In case people haven't heard of it:

Cold reading is a series of techniques used by mentalists, psychics, fortune-tellers, illusionists, and con artists to determine or express details about another person, often in order to convince them that the reader knows much more about a subject than they actually do.[1] Without prior knowledge of a person, a practiced cold reader can still quickly obtain a great deal of information about the subject by analyzing the person's body language, age, clothing or fashion, hairstyle, gender, sexual orientation, religion, race or ethnicity, level of education, manner of speech, place of origin, etc. Cold readers commonly employ high probability guesses about the subject, quickly picking up on signals from their subjects as to whether their guesses are in the right direction or not, and then emphasizing and reinforcing any chance connections the subjects acknowledge while quickly moving on from missed guesses.

-From wikipedia

How to Draw Conclusions Like Sherlock Holmes? Become a fictional character and point out all the details your author has included to move the plot forward.

Maybe my old comment on Rationalist Fiction is worth reposting here.

"In defense of Conan Doyle, Wikipedia says:

Sherlock Holmes remains a great inspiration for forensic science, especially for the way his acute study of a crime scene yields small clues as to the precise sequence of events... All of the techniques advocated by Holmes would later become reality, but were generally in their infancy at the time Conan Doyle was writing.

and goes off to claim that later detective fiction actually became less realistic as writers shifted attention to psychology rather than forensics."

I think, Arthur Conan Doyle - the author of Sherlock Holmes - was one of the great rationalists of the 19th century. So was his mental child, the famous detective. And his methods are very rational in essence.

Dos not matter what Yudkowsky thinks or writes.

What a reaction!

And what claims. That Socrates not believed in Zeus. What else did he do in Delphi? Which god did he obeyed by his own claims, if it wasn't Zeus? And what better that would be?

But let us talk about Newton who's birthday wants to replace Jesus's birthday. He was a religious man also. Mildly put. Not to mention his Demonology, the dragons an such for a lay person? See.

Hundreds of examples out there, of scientists who were rational only in there narrow field and quite deluded elsewhere.

Arthur Conan Doyle is no forum darling, I know. And his spiritualism WAS silly, I admit that. But why to bash him about it and not almost everybody else 100 and more years ago about there believes in gods (which are not inherently more real then ferries are)?

One can take Newton's laws and the Calculus and the prism and say thank you very much for the rest of him, I don't need it, it's garbage.

The same with Conan Doyle. Some of us credit him for putting logical reasoning to the highest place in his literature. The rest is mainly garbage, of course.

It is always this way in humans. Some pearls in trash.