Cool, so basically; if a person creates it with artistic intentions, then it's art.
Alternately, if the person observing it thinks of it artistically, then it's art.
A bit of a flaky definition, but the artistic nature of an object can be determined by either the creator or observer. What's interesting about that is that non-art can become art simply by observing it, or by changing it's context.
On the flip side, think of the Basilica Cistern, where they used former artwork as pillars to hold up the roof. In this context art has been used purely for function - is it still art? The 'creators' used an artistic component as a functional object, and the observers were engineers considering functional aspects. A few thousand years later, the artistic value is rediscovered. Can we conclude that the label of 'art' is ephemeral - something can become art or non-art as the times change?
A related question is 'can nature be art'. Can an elephant or dolphin create art? I'm sure you've heard of (or can google) instances of dogs or elephants creating paintings, can this still be considered art? And if so, why? We previously established (or I tried to establish) that at least one of two parties must consider the artistic value for it to become art. Can a dog consider something to be artistic? Or is it purely on the shoulders of the human observer?
If the burden is purely on the human observer, then can we consider an ordinary tree to be art? If we appreciate the texture, the form, the colors, is it art? Obviously flowers and animals are appreciated, but are they art? Can the Earth, the moon, the Sun, be considered art? What about difficult to observe things like air, a vacuum, rays of light? Or impossible to observe things like quarks or kinetic movements like vibrations? What about purely non-physical things - mental, spiritual, intellectual - like ideas, concepts, arguments, emotions?
tl;dr:
- can non-humans create art?
- can non-sentient create art?
- can non-life create art?
- can non-observable physical phenomenon be art?
- can non-physical phenomenon be art?