We egocentric humans have been reluctant to grant that any other creatures have minds like ours. Although that may be partly true—the human mind is the most complex one on Earth—ongoing research is demonstrating that most animals indeed have quite sophisticated minds. In fact, until the last several decades, many people did not believe that animals had a mind at all; but were more like automatons who also had no feelings. We can thank Rene Descartes for this idea, who, in the 17th century, viewed animals as more like unconscious, stimulus-response machines.
Fortunately, more and more of the solid barriers we once thought God had erected between us and other creatures are collapsing. For example, many recent clever experiments have demonstrated that animals make and use tools, recognize themselves in mirrors, have a sense of self, use symbolic communication, solve complex problems, and display other complex, cognitive abilities. Charles Darwin was way out in front of the effort to see similarities, when he wrote, “There is no fundamental difference between man and the higher mammals in their mental faculties.”
Despite these similarities in cognitive abilities, there is one barrier that we may never surmount: knowing what it's like to be another creature. Although our minds may work in roughly similar ways, the sensory inputs to minds are often very different. A dog's sense of smell is far greater than mine, so how its brain interprets its world will be heavily swayed by aromas that I am ignorant of. Our worlds will feel different. An eagle's eyes are for more acute than mine, so its visual world will be quite different from mine. Yet neither a dog nor an eagle can count to 10 or build a smart phone, so we likely will never be able to bridge the gap between us, to know what it's like to be the other. We are shut out from each others' imaginations and perceptions.
Current experiments in the field of ethology (animal behavior) are demonstrating that many animals respond to their environment in similar ways that we do. It's only reasonable to assume that they have comparable intentions and feelings. We can see that they also must represent their world internally, but because our senses are so different, we cannot know how it feels to them. Other research has shown that even plants possess sentience of some sort; even they have some kind of mind.
These findings will likely be very relevant, if we some day discover extraterrestrial life. If we can't imagine what it's like to be a bird or a bat on Earth, how will we fare when we meet aliens whose sensory inputs may be exotically different? Like Descartes once thought about dogs and cats, we may not even recognize that alien life possesses a mind, when in fact their minds may make ours appear quite primitive—like an amoeba.
