To the best of our knowledge humans are the only species that think symbolically.
That is, we can imagine something and represent it using a symbol so we can then use it for our benefit. (Or our non-benefit)!
For example, in ancient times, before writing, we began to use words as symbols to describe things. We then used lines and circles and squiggles of various kinds to make up letters to write down the words that we were using so we could communicate them non-verbally. As we became more technological, the worlds of mathematics, physics, chemistry and many other sciences were based on symbols representing things unknown and known.
A map is a good example of representing something symbolically. Rivers are usually depicted in blue, and motorways by thick lines, and minor roads using thin lines. Railway lines are almost always black and thinner than roads. Churches are usually represented by crosses – in the Western World anyway. There is always an arrow pointing N (north), and all maps have to have a scale, that is, an indication of what large distance on the ground is represented by a small measurement on the map. (For example, one cm on a map could be 100 km on the ground).
Anyone who is a driver, and who has done the Theory Test, will know all about symbols!
Getting away from physical symbols, such as those described in the paragraphs above, we can imagine the future for ourselves, see ourselves in a different setting, perhaps going for an interview, getting a new job, doing an exam, changing careers, getting married, planning a new garden, going on a journey, knitting a garment, having children etc. etc. All these involve, to some extent, thinking symbolically.
Imagination is important in human development. To imagine something and then try and transform what is in our imagination into reality is – when we think about it – amazing.
We can also use our ability to think symbolically to draw a picture, from our imagination, of something that we find it difficult to describe with words. The expression a picture’s worth a thousand words comes to mind here. This could be a concept, or something abstract. For example, music can be symbolically displayed by writing lines, squiggles, shapes etc. Something that is unknown, that we want to find out more about, can be represented by a symbol in mathematics.
All our literature, poetry, art, music, science, engineering, inventions, architecture, etc. are possible because of our ability to think symbolically.