If and unless are common conditional conjunctions employed to express conjecture and uncertainty, but a number of other words and phrases that perform similar functions are discussed in this post.
“Should you” is the future conditional form of “do you,” seen in formally polite requests such as “Should you have any questions, please do not hesitate to contact me.” It is more flexible than “if you,” which is strictly conditional in the present, in inviting the audience to contact the speaker/writer at any time, not just now.
“Had you” is an example of a subject-auxiliary inversion, employed in statements such as ‘Had you bothered to ask, I would have told you.” The implication of the sentence is that the audience did not do something that, if he or she or they had, would have achieved the stated result.
“If (noun/pronoun) were” statements pertain to possible but improbable occurrences or to recommendations, as in “If you were to open your eyes, you would find what you were looking for.” A more formal version of this form is “were (noun/pronoun) to (verb),” as in “Were we to think otherwise.”
Several words or phrases impose conditions or set limits, such as “As long as” (less formal) or “so long as,” (more formal), “only if,” “on condition that,” and “provided” or “providing” (or “provided/providing that”).
The conjunction or is used conditionally to establish an alternative possibility to a condition or state: “Hurry up, or you’ll be late.” Otherwise, as used earlier in this post, is a pronoun; as a conjunctive adverb, it serves the same function as or (but notice the difference in punctuation): “Hurry up; otherwise, you’ll be late.” (Some writing guides accept the punctuation used with or.)
Suppose and supposing apply to what-if situations: “Suppose that I were to say no—what would you do?” “Supposing that I were to say no, what would you do?” Suppose also pertains to proposing an idea, as in “Suppose I pay for dinner, and you buy the movie tickets?”
In “if only,” only appears as an intensifier to express a strong wish for a different condition or state, as in “If only you had told me before.” “If so” and “if not” pertain to opposite potential affirmative and negative conditions or states, respectively, when the condition or state is known: “Do you plan to attend the event? If so, click on yes. If not, click on no.” Even is also used as an intensifier with if, but unlike in the case of only, it precedes if; it pertains to extreme or surprising conditions or states, as in “Even if I were to believe you, what would you expect me to do about it?”
You have left out all consideration of the conditional word “whether”.
In English, we often use “if” in places where it means “whether”: “I cannot tell if that being is a man or a woman.” This really means , “I cannot tell whether that being is a man or a woman.” (There are two possibilities.)
In German, this is quite important because there are two different words to choose from correctly: “wenn” means “if”, and “ob” means “whether”. Confusing things more (false cognates), “wann” means “when”.
More complications:
“wenn auch immer” means “whenever”,
“sooft ich kann” means “whenever”, and
“wann auch immer” means “whenever”,
and “immer” means either “ever” or “always”.
Also, there are about seven different ways to say “why”,
including {warum, wozu, weshalb, wieso, weswegen,…}.
“Wieso um um alles in der Welt?” = “Why on earth?”
Why on earth with all of these complications?
Part of the reason is whether “why” is used as an interrogatory or as a relative adverb.
“I don’t know why some people think that the world is flat.”
There is also a Japanese expression that means “Bringing the six corners of the world under one roof.” Is the world a cube?
Or maybe that is eight corners.
D.A.W.
Does “else” (also “or else”) qualify as a conditional?
ELSE!
A long time ago in computer programming, there was only one kind of conditional instruction in a program: The IF statement. It generally went like this. Let A be some statement that can be true or false.
For example, n > 5. So the conditional statement is: IF(A) THEN GO TO 200, where 200 is the line number of some other place in the program (where there is a different command for the computer to execute). In the case where A is false, the program does nothing but to go on to the next line, which might be line 105.
This gets complicated after a while, so people invented a new kind of conditional, the “IF THEN ELSE” statement. One of these could go like this: IF(A) THEN LET n = n + 1, ELSE LET n = n – 1 .
This actually makes the program a lot easier to write and to understand.
The next invention was a conditional statement that could go three ways. It goes like this, where X is some number:
IF(X) THEN 200, 400, 600 , where these are three line numbers in the program.
What this does is the following: with X 0, the program goes to line 600.
So to write that in plain English:
Whether X is positive, or negative, or zero, then accordingly,
GO TO line 200, or GO TO line 400, or GO TO line 600.
I put this last one in specifically to illustrate the use of the word “whether”. “Whether” usually implies three or more possibilities, but in English, this is not always the case.
One could ask, “I wonder if that creature is male or female.”
Well, there are other implicit possibilities: That creature (or human being, or an extraterrestrial) could be a hermaphrodite, or a sexless being.
Oh, this silly system “bleeped out” a lot of my words because I used inequalities: those symbols that look like > and < .
Here are the corrections, w/o nasty symbols for this computer system<
What this does is the following:
with X less than 0, the program goes to line 200,
with X equal to 0, the program goes to line 400,
with X greater than 0, the program goes to line 600.
At each of these three line numbers, there are different commands for the computer to execute.
Henry the Eighth might have said:
with X less than 0, Off with her head!
with X equal to 0, Let her go into exile!
with X greater than 0, Feed her to the sharks!
With all of those six wives, Henry VIII had a son and two daughters:
Edward became the king, but he did not live too long.
Queen Mary became the monarch, but she was a devout Catholic, and her father had made England a Protestant country. Thus, they found a way to get rid of “Bloody Mary”.
Her younger sister became Queen Elizabeth I, but she never married, and she left no heirs, and that was the end of the House of Tudor.
(The British have had a lot of three-way decisions!)
Elizabeth I did reign longer than any British monarch before her.
Her record was broken by Queen Victoria, a descendant of the King Georges of Brunswick, Hannover, Hesse, etc. (Including the Hessians who fought in our Revolutionary War on the side of King George III.)
Victoria’s record was recently broken by Queen Elizabeth II of the House of Windsor. (This name was chosen during World War I to get rid of the old trinary German name of Saxe-Coburg-Gotha.)
The long-reigning Queens of England have come in threes
All of King George V, Kaiser Wilhelm II of Germany, and Czar Nicholas II of Russia were descendents of Queen Victoria, and her husband, Prince Albert, was a native of Germany, too. That was where “Saxe-Coburg-Gotha” came from.
Oh, well, the monarchs of Denmark, Norway, Belgium, are all descendants of Victoria, and also are the former monarchs of Greece, and also is the husband of Queen Elizabeth II, Prince Phillip Mountbatten!