Difference between a Metaphor and a Simile
Metaphor and simile are quite different, but are commonly confused simply because
they are so very similar in nature. This chapter is aimed at clearing up at least some of
the confusion, if not the entire sum of the confusion! As you read on, you'll learn why
these two are so similar, and how to clearly separate the two. First, have a look at the
following two examples.
A good book is like a good meal. A simile suggesting that a book may be as ( mentally)
nourishing and satisfying as a meal.
A wire is a road for electrons. A metaphor suggesting that electrons actually do use a
wire as a road to travel on.
If I had said above that "a book is food for thought" rather than "a good book is like a
good meal", I would not simply be comparing food and literature, but actually stating
that from some perspective they are identical. If I am an avid reader, who hungers for
information to digest, gleaning every detail to feed my insatiable appetite for brain
candy, literature is not only similar to food for me - it is food.
A simile - or to be like something - is to retain some irresolvable difference which
means one can never fully substitute for the other. On the other hand, a metaphor
actually is a substitution - it is an equation in principle.
It could be said, then, that:
A metaphor is an equation where a simile is an approximation.
In math, I could say that 99 is approximately equal to (or "like") 100 - that would be a
simile - a comparable but different value ("about 100"); but an equation, such as A=B,
means that if A+3=10 then B+3=10. A simile may be difficult to extend further in this
way, but the nature of a good metaphor is that it may always be extended, reversed,
re-substituted with other elements and so on (just as an algebraic expression* can). In
fact, using the above equation, I may also find that another metaphor "C" is also equal
to A and B, such that A=B=C. For example:
A road is a road for cars.
A wire is a road for electrons.
A vein is a road for blood cells.
The sea is a road for ships.
The railway is a road for trains.
To show how interchangeable these are, let's look at a few common phrases (metaphors
shipping lane/ highway lane
electric line/ railway line/ shipping line/ gas line
major artery for traffic
electric conductor/ train conductor/ bus conductor
rail road/ iron road
path of electrons
traffic flow/ electron flow/ blood flow
(One may even convey a point in their line of conversation by steering the
conversation to flow in the direction of a specific avenue)
Sometimes, we will build both a metaphor and a simile from the same parts, showing
how incredibly close these two literary devices are. Perhaps this is due to the fact that
the word "like" means both "similar" and "the same". Compare "a car is like a cell: it
travels along a vessel of asphalt" with "a car is a cell...". When building a simile, it
helps to keep it clearly removed from a metaphor: "clouds like cotton candy" is clearly
Typically, if it needs further explanation, it's probably a simile; if it makes instant sense,
it's most likely a metaphor. The simile is always poetic, while the metaphor always has
the ring of truth (perhaps this is why metaphors readily become accepted into language
as "dead metaphors", while there is no such thing as a "dead simile").
Basic Rule: If it uses the words "is like" or "is as", it is usually a simile; if it uses the
word "is", without "as" or "like", it is usually a metaphor. Caveat: Because there is so
much confusion surrounding the difference between metaphor and simile, the two are
often misstated. If the word "like" is used to imply similarity, then it is a simile;
however, if the word "like" is being used to imply it is "the same", then this is a false
simile and is, in fact a metaphor.
Simile: ABC is approximately equal to DEF;
Example: "clouds like cotton candy"
"Cloud" = ABC...= White Light Gaseous;
"Cotton Candy" = DEF...=White Light Soft
Gaseous is not equal to soft. However, they are similar in their accommodating nature.
Though clouds may look like cotton candy, their functions within their respective
domains are entirely different. Truthfully, the clouds are not like cotton candy, but they
leave a passing impression that they are. A simile is almost always based on our first
impressions, which is why the comparison drawn in a simile is always limited.
Metaphor: ABC equals DEF; A=D, B=E, C=F ;
Example: "a car is a cell"
"Car" = ABC...= Shell Doors Wheels;
"Cell" = Wall Pores Cilia***
A car is equal to a cell. Both protect and transport their passengers, and allow material
and passengers in and out. Both breathe, pollute and need energy to function. Their
functions within their respective domains are identical. This means that many of the
relationships found in one domain will be found in the other, which is why an equation
formed in a metaphor is always expandable.
Eg: "Sugar is the fuel of the cell"; "Traffic flows quickly on major arteries". The
evolution of the car has led from a metal shell to a tough flexible polymer shell, which
closely resembles the material used in cell walls. Car alarms and keys have evolved to
separate intruders from guests, matching systems used by cells to prevent unwanted
foreign bodies from entering and taking over the cell. Fuel cell technology is closing in
on the same proton exchange techniques used in all cells, and terms such as "motor"
are used in biochemistry**** . The car is evolving to become even more cell-like,
and new metaphors within this system will arise with each new cellular discovery or
automotive invention. (It could be said that nanotechnology will be the meeting place
of many, many metaphors).
A short list of distinguishing characteristics:
"A metaphor is an equation where a simile is an approximation."
"A metaphor can always be greatly extended, while a simile quickly reaches its limits."
"The words like or as are widely known hallmarks of the simile - but there are so many
faux similes bearing these hallmarks that further appraisal is always needed."
"A metaphor dies of exhaustion; a simile just gets more and more tired."
Exercise: Build your own metaphor !
Here are several common statements using words that are already metaphors, or are
easily replaced with metaphors. Try to make working statements by substituting one or
more italicized words with their counterparts below.
A wire conducts electrons; electric current flows along a wire; water current streams
along a course; traffic moves along a road; a bottleneck in traffic slows the flow of cars;
water runs along a pipe; electric lines, plumbing/sewer lines, railway lines; railway
cars; path of electrons; a backed-up drain; backed-up traffic; traffic is running
smoothly; blood flows down an artery;
wire = road = course = pipe = line = path = artery (Notice that each is a "hollow"
line, that can allow movement along itself.)
electrons = water (molecules) = cars = blood (cells) * (Notice that each is an object
or a single group of objects that may travel together.)
flow = run = move = stream = pass (Notice that each is a steady movement - an
indication of traveling a distance over a period of time.)
"water current flows along a course" becomes "electric current streams along a path"
"blood flows down an artery" becomes "(a) train runs down a line"
A system can behave as a single object, as well: for example "the system is running
smoothly". Try to find a few systems to substitute in the above statements, such as "the
mail service is running smoothly" or "the paperwork is backed-up"
Note: If an expression doesn't seem to work, see if you can find the needed
element that will make the statement work. Such "adjustments" will really
help you understand what you already know, and help you create very coherent
and extensive metaphors.