Sentience is the manifestation of a mind, linked to intelligence and cognition. Sentient beings display the properties of consciousness and intelligence. The idea of sentient beings extends to other animals but not to plants. Plants have a strategy of existence, remarkable forms, beauty and adaptability, but no minds. In a modern sense, sentience is a composite property of brains that varies approximately with the size, organization and complexity of the brain.
A hierarchy of sentience exists in the living world. The hierarchy of sentience follows an evolutionary path with the oldest creatures such as worms and shelled creatures of the sea at the lowest levels of sentience.
Mammals are more recent and more elaborate creatures with high levels of sentience. Humans are mammals and have a natural affinity for some but not all other mammals. Thus, it is reasonable to assume that dolphins, whale’s, apes and humans have similar sentience. While dogs are sentient beings with consciousness, feelings and behaviors that are mostly congruent with human feelings and behaviors, they have smaller, more specialized brains. It is reasonable to assume that dogs operate at a somewhat different level of sentience.
Chimpanzees and Bonobos are our closest primate relatives; their sentience is similar to ours and they deserve our protection and respect. When you examine human and chimpanzee cognitive abilities in detail, there are differences between their ability and ours. For example, chimpanzees can learn “language” from human teachers, using symbols, signs and keyboards, but they are unlikely to create a virtual reality from sounds and symbols as humans do. Their social communications are rich and complex, however, and provide us with insights into the development of human spoken language.
Members of the philosophy departments at universities point to books and journal papers as evidence of the thought process and will cite intelligent argument or “reason” as the indispensable tool of philosophy.
The word “thought” is not so easily defined. In common use, thinking is equivalent to selftalk, the process of talking to yourself when you are not busy doing other things. Selftalk has important limitations that need to be understood before human cognitive processes can be understood. Self talk extends to conversation as group thinking, lectures, books and the constant chatter of media.