NYU Professor Thomas Nagel (1974) asked a rather unusual question.
What is it like to be a bat? Do animals think?
The article can be found here: http://www.cs.helsinki.fi/u/ahyvarin/teaching/niseminar4/Nagel_WhatIsItLikeToBeABat.pdf
This article is not really about whether or not animals think. It's about the subjective concept of experience.
Here's a way to approach it:
1. Nagel is worried about consciousness - something akin to awareness. If other organisms have it, then there must be a sense that "being" that organism is something real - almost like having a personality of sorts. We're really talking about awareness and a sense of purpose.
2. Since the bat lives very differently from humans (the way it senses via sonar is just the beginning), the experience of being a bat is totally inconceivable for us.
3. If we are worried about how a bat experiences things, we cannot think of it as of WE are living as a bat. That makes no sense - we have to see how a bat lives as a bat.
4. When a bat is hungry, say, what does this hunger feel like? How is it experienced? WE cannot import our own experiences with hunger, since we have no evidence that bats feel it (or "consider" it) in a way similar to us.
5. This implies that being a bat has a language, a set of concepts that can only develop insofar as you're actually a bat. The way humans consider things generates its own set of ideas that cannot be exported onto the animal world.
6. Experience is the connection between out subjective states, and the "external" objective reality of the world. This means that experience is mediated by who we are: human ...
The expert examines what it is like to be a bat. Whether animals think are determined.