The traditional "heart shape" appears on a 1910 St. Valentine's Day card. The heart () has long been used as a symbol to refer to the spiritual, emotional, moral, and in the past also intellectual core of a human being. As the heart was once widely believed to be the seat of the human mind, the word heart continues to be used poetically to refer to the soul, and stylized depictions of hearts are extremely prevalent symbols representing love. However, more realistic depictions of human hearts tend to have macabre connotations of death and violence, quite unlike the concepts associated with the poetic and symbolic heart. This discrepancy is a common source of dark humor.
In mythology, spirituality and religion
In religious texts such as the Bible, the heart has historically been ascribed much mystical significance, either as metaphor or as an organ genuinely believed to have spiritual or divine attributes.
In the Bible, this idea emerges in the earliest passages; Genesis 6:5 situates the thoughts of evil men in their hearts, and Exodus 5 through 12 speak repeatedly of the Lord "hardening Pharaoh's heart." By this it is meant that God made Pharaoh resolve not to let the Israelite slaves leave Egypt, in order to bring judgment against Pharaoh and demonstrate his power: "'Go to Pharaoh, for I have hardened his heart and the hearts of his officials so that I may perform these miraculous signs of mine among them'" (Exodus 10:1).
In the Book of Jeremiah 17:9, it is written that the "heart is deceitful above all things, and desperately wicked," and that the Lord is the judge who "tries" the human heart.
Similarly, in Egyptian mythology, the heart was weighed in a balance against the feather of Maàt, symbolizing truth, in the judgment of the dead in the Egyptian Book of the Dead. Should the heart be heavier than the feather, the judged person would suffer in hell, since his heart was weighed down with sins. However, if the heart was lighter than the feather, the owner of the heart was admitted to paradise (See also Egyptian soul).
In early science and philosophy
Many classical and medieval philosophers and scientists, including Aristotle, considered the heart the seat of thought, reason or emotion, often rejecting the value of the brain.
The Roman physician Galen located the seat of the passions in the liver, the seat of reason in the brain, and considered the heart to be the seat of the emotions. While Galen's identification of the heart with emotion were proposed as a part of his theory of the circulatory system, the heart has continued to be used as a symbolic source of human emotions even after the rejection of such beliefs.
The Stoics taught that the heart was the seat of the human soul.
European traditional heart symbol. In European traditional art and folklore, the heart symbol is drawn in a stylized shape. This shape is typically colored red, suggesting both blood and, in many cultures, passion and strong emotion. It and diamonds are the two red suits in most playing card decks. The shape is particularly associated with romantic poetry; it is often seen on St. Valentine's Day cards, candy boxes, and similar popular culture artifacts as a symbol of romantic love.
What the traditional "heart shape" actually depicts is a matter of some controversy. It only vaguely resembles the human heart. Some people claim that it actually depicts the heart of a cow, a more readily available sight to most people in past centuries than an actual human heart. However, while beef hearts are more similar to the iconic heart shape, the resemblance is still slight. The shape does resemble that of the three-chambered heart of the turtle, and that of the human male prostate gland, but it is very unlikely that the image was patterned after either of these organs.
Ancient silver coin from Cyrene depicting a silphium seed or fruit. The "heart" shape could also be considered to depict features of the human female body, such as the female's pubic mound or vulva. A Sumerian cuneiform symbol for "woman" closely resembles the heart shape, and is believed to directly depict the pubic mound. Others maintain that the heart resembles the shape of the female breasts or the female buttocks.
Another possible origin can be seen on the coins of the ancient city of Cyrene, some of which depict the seeds or fruit of the now-extinct silphium plant. The seeds are distinctly heart-shaped. Since this plant was widely used as an ancient herbal contraceptive or abortifacient, this shape may have come to be associated with sexuality and love.
Mating Mute Swans may appear to make a negative space heart.The most common emoticon for the heart is <3. In Unicode, the heart symbol is U+2665, and it can thus be generated in HTML by typing ♥ or ♥, or by the HTML entity ♥. Mathematically, a heart-shaped figure, called a cardioid, can be represented by plotting a graph of either (x2 + y2 − 1)3 = x2y3 or, in polar form, r = 1 − sin(θ)
I (pronounced "I love" or "I heart") is a slang expression used to indicate love or affection, sometimes with a connotation that the feeling is superficial or juvenile. It is a play upon Milton Glaser's classic logo, I NY (pronounced I Love New York). In the U.S., it is often written by schoolchildren to indicate a "crush" on another person. It is also present is some recent titles, e.g. the film I Huckabees or the video game We Katamari.
The widespread use of this expression has inspired many parodies. Originally pronounced "I love", the phrase has recently been used by young hipsters who have taken to facetiously verbalizing it as "I heart". Other examples include:
Parody bumper stickers have included "I My Cat" (spade being a homonym and common pun for spayed) or "I My Wife" (club meaning blunt object and spousal abuse).
A The Far Side cartoon by Gary Larson pictured Godzilla driving a car with an "I 8 NY" bumper sticker (8 meaning ate).
Playboy once reported that a novelties manufacturer was offering little square stickers picturing a screw (representing a vulgar slang term), to be placed stealthily over the heart in stickers such as "I My Pomeranian" or whatever breed.
T-shirts parodying this phrase and Unicode have read "I Unicode", being the "replacement character" used on a Macintosh when the font in question does not contain a graphic for the Unicode character in question, or "I Unicode", as some Windows fonts show.