That is a bit philosophical question. And even though most you would without hesitation answer yes, is it really true? What is in fact sound?

This question was presented to me during lecture about perception at my university. And I would like to share with you what I learned. Because we can actually use the word sound in two different ways.

Physical definition

In a physics sound can be defined as changes in pressure in the air or other medium. In this sense the answer is clearly yes, because falling tree that consequently slams to the ground will definitely create these changes. And this does not change whether there is or is not someone to actually hear it.

Perceptual definition

On the other hand, sound can be defined as the experience we have when we hear. So, according to this definition sound is only sound when there is someone to hear it. If not, then that is only a set of changes in air pressure, but nothing else. So, in this case the tree would not make any sound.

It is all about the context

As in most cases this is also about context. This particular tree in empty forest would or would not produce sound according to which definition of sound is being used. Usually humans can distinguish quite easily whether we are talking about perception of sound (The sound of her voice was comforting.) or about sound in the context of physics (The sound level was 5 dB.).

Do we shape the world?

I know that this was quite short and philosophical article, but it actually makes sense. A bit. I think that the same logic goes for other things as well, such as colours. Only thanks to us there are colours, because we perceive them as such. Maybe some alien species would perceive colour and sound much differently. These are quite strange and dangerous waters for me, because yes, for me the answer to the question about tree is YES. To me the physical definition is the correct one. But the perceptual definition makes somewhat sense as well. It is like we shape the world in a way, our senses give raise but also limit our observations. We give labels to tastes, colours, smells, sounds – but without us there would be no meaning to them. It is WEIRD.

So, hopefully you did not die of boredom and maybe had to think about and question the world a bit, haha. This is something different than my usual topics- but heck, so what.

Have a great day! :)