This is why Hameroff and Penrose propose that while survival to reproduce is fundamental, the urge to actually mate for procreation is derived from the experience of "pleasure", a parsimonious state of organization. Note: sentience is not the same as intelligence and does not necessarily require a brain at all. What we call pleasure is from the production of Dopamine.. But there may many other mechanisms that produce a physical state of parsimony in non-brained organisms. In fact Penrose proposes that this phenomenon already occurs abstractly in "bonding" at quantum level. I mentioned the Table of Elements before. One can readily see that the protons, electrons, and neutrons are all arranged in specific and orderly mathematical patterns, which we attribute to the "attractive" properties between those quantum particles. Certain elements lack this stability and become radio active. http://www.atomicarchive.com/Physics/Physics5.shtml The same thing happens with building molecules. Their mathematical arrangements are always parsimonious. If not, they become unstable and revert to a simpler state. In my book all of the universe is mathematical in essence and with that I mean everything has a specific "value". When these values are "compatible" they will bond and form patterns, starting at quantum (atomic) level to complex organisms. All are fundamentally arranged by their mathematical values each which reinforces the whole. That is the Evolutionary process. Mutation and Natural Selection are natural probabilistic events. The more complex the organism the greater the probability for something going wrong and the mathematical processing between the system's information network becomes injured or is broken, usually results in detrimental effects, but once in awhile the error results in a beneficial trait to the organism. A beneficial "mutation". Of course the next day a meteor may smash on top of that organism and that would be "natural selection".....Please Register or Log in to view the hidden image! But considering the astronomical mathematical values we are dealing with, any beneficial traits usually will survive and gain an advantage in survivability in order to find a mate.....Please Register or Log in to view the hidden image! IMO, Sentience is the ability to experience change in "some form" of symmetry between comfort and discomfort by the exchange of information mathematical or biological in the functions of the organism, must be present because it provides "motive". And self-aware motivation provides purpose and meaning to the whole of the organism. My cat can't wait until I sit down to watch TV, the moment I am comfortable, he is on my chest, purring and scenting me with his cheeks. He knows that when I stroke him his personal goal to be stroked will have been achieved. Parsimony. As I understand Penrose, he thinks it goes even deeper.