Faith

Faith is often described as belief without evidence.  The famous definition in Hebrews, in its best-known form, is close to that:

"Now faith is the substance of things hoped for, the evidence of things not seen." - Hebrews 11:1 (King James Version), often attributed to St. Paul

This is the way the term "faith" is used by religious people when they argue against the primacy of reason, as demonstrated in these quotes, which is the context I am concerned with.  (It's also the meaning used by atheists arguing against religious faith, eg. Sam Harris in The End of Faith.)  But the New International Version, which is less pretty, but translated more carefully by better scholars from more and older texts, says:

"Now faith is confidence in what we hope for and assurance about what we do not see."

The Wikipedia and Plato entries on faith give information on the use of words translated as "faith" in English in different religions and philosophies.  Wikipedia cites the New American standard exhaustive concordance of the Bible as saying,

In English translations of the New Testament, the word faith generally corresponds to the Greek noun πίστις (pistis) or the Greek verb πιστεύω (pisteuo), meaning "to trust, to have confidence, faithfulness, to be reliable, to assure".^[22]

Theory

Scientific theory is also assurance about things unseen.  (If you can observe something directly, you don't need science.)  Science builds an abstract mental structure that interprets data and makes predictions from it.  It is also an epistemology for belief in things we can't see, like atoms, oxygen, radio waves, vast distances, or circulation of the blood.

The history of faith and theory

The most popular belief appears to be that faith is ancient, and scientific theory came along later to supersede it.  But I'm not aware of evidence for this.

There have been many previous discussions here on cryonics and why it is perceived as threatening or otherwise disagreeable. Even among LWers who are not signed up and don’t plan to, I’d say there’s a good degree of consensus that cryonics is reviled and ridiculed to a very unjustified degree. I had a thought about one possible factor contributing to its unsavory public image that I haven’t seen brought up in previous discussions:

COLD is EVIL.

Well, no, cold isn’t evil, but “COLD is EVIL/THREATENING/DANGEROUS/HARSH/LONELY/UNLOVING/SAD/DEAD” seems to be a pretty common set of conceptual metaphors. You see it in figures of speech like “cold-hearted,” “in cold blood,” “cold expression,” “icy stare,” “chilling,” “went cold,” “cold calculation,” “the cold shoulder,” “cold feet,” “stone cold,” “out cold.” (Naturally, it’s also the case that WARM is GOOD/COMFORTING/SAFE/SOCIAL/LOVING/HAPPY/ALIVE, though COOL and HOT sort of go in their own directions.) Associating something with coldness just makes it seem more threatening and less benevolent. And besides, being that “COLD is DEAD,” it’s pretty hard to imagine someone as not really dead if they’re in a container of liquid nitrogen at -135ºC. (Even harder if it’s just their head in there… but that’s a separate issue.) There is already a little bit of research on the effects of some of the conceptual metaphors of coldness and the way its emotional content leaks onto metaphorically associated concepts (“Cold and lonely: does social exclusion literally feel cold?”; “Experiencing physical warmth promotes interpersonal warmth.”; any others?).

A word's denotation is our conscious definition of it.  You can think of this as the set of things in the world with membership in the category defined by that word; or as a set of rules defining such a set.  (Logicians call the former the category's extension into the world.)

A word's connotation can mean the emotional coloring of the word.  AI geeks may think of it as a set of pairs, of other concepts that get activated or inhibited by that word, and the changes to the odds of recalling each of those concepts.

When we think analytically about a word - for instance, when writing legislation - we use its denotation.  But when we are in values/judgement mode - for instance, when deciding what to legislate about, or when voting - we use its denotation less and its connotation more.

This denotative-connotative gap can cause people to behave less rationally when they become more rational.  People who think and act emotionally are at least consistent.  Train them to think analytically, and they will choose goals using connotation but pursue them using denotation.  That's like hiring a Russian speaker to manage your affairs because he's smarter than you, but you have to give him instructions via Google translate.  Not always a win.

Consider the word "human".  It has wonderful connotations, to humans.  Human nature, humane treatment, the human condition, what it means to be human.  Often the connotations are normative rather than descriptive; behaviors we call "inhumane" are done only by humans.  The denotation is bare by comparison:  Featherless biped.  Homo sapiens, as defined by 3 billion base pairs of DNA.