While life in general can be explained by the mechanisms of physics, chemistry and biology, to many scientists and philosophers it appears that when it comes to explaining consciousness, there is what the philosopher Joseph Levine called an “explanatory gap” between the physical brain and subjective experiences. Here we deduce the living and neural features behind primary consciousness within a naturalistic biological framework, identify which animal taxa have these features (the vertebrates, arthropods, and cephalopod molluscs), then reconstruct when consciousness first (...) evolved and consider its adaptive value. We theorize that consciousness is based on all the complex system features of life, plus the even more complex features of elaborate brains. We argue that the main reason why the explanatory gap between the brain and experience has been so refractory to scientific explanation is that it arises from both life and from varied and diverse brains and brain regions, so bridging the gap requires a complex, multifactorial account that includes the great diversity of consciousness, its personal nature that stems from embodied life, and the special neural features that make consciousness unique in nature. (shrink)

Birch, Ginsburg, and Jablonka, in an article in this issue of Biology and Philosophy, provided a much-needed condensation of their well-reasoned theory of Unlimited Associative Learning. This theory compellingly identifies the conscious animals and the time when the evolutionary transition to consciousness was completed. The authors convincingly explained their use of UAL as a “transition marker,” identified two more features by which UAL can be recognized, showed how UAL’s learning features relate to consciousness, and how investigating consciousness is analogous to (...) investigating life. My constructive criticisms are that I wish they had taken a stand on which organisms and entities are not conscious, and I feel they made too many predictions by which to test the UAL theory. That is, some of the proposed tests are unnecessary because parts of UAL are already supported by enough evidence, and other proposed tests are so ambitious as to be nearly impossible to complete. Finally, UAL has a major, detailed, sub-hypothesis that says such learning led to stress and to the evolution of mechanisms to cope with this stress; but this idea is speculative and requires the most basic testing to judge whether it could be valid. (shrink)

The multiple realizability thesis (MRT) is an important philosophical and psychological concept. It says any mental state can be constructed by multiple realizability (MR), meaning in many distinct ways from different physical parts. The goal of our study is to find if the MRT applies to the mental state of consciousness among animals. Many things have been written about MRT but the ones most applicable to animal consciousness are by Shapiro in a 2004 book called The Mind Incarnate and by (...) Polger and Shapiro in their 2016 work, The Multiple Realization Book. Standard, classical MRT has been around since 1967 and it says that a mental state can havevery manydifferent physical realizations, in a nearly unlimited manner. To the contrary, Shapiro’s book reasoned that physical, physiological, and historical constraints force mental traits to evolve in just a few, limited directions, which is seen as convergent evolution of the associated neural traits in different animal lineages. This is his mental constraint thesis (MCT). We examined the evolution of consciousness in animals and found that it arose independently in just three animal clades—vertebrates, arthropods, and cephalopod mollusks—all of which share many consciousness-associated traits: elaborate sensory organs and brains, high capacity for memory, directed mobility, etc. These three constrained, convergently evolved routes to consciousness fit Shapiro’s original MCT. More recently, Polger and Shapiro’s book presented much the same thesis but changed its name from MCT to a “modest identity thesis.” Furthermore, they argued against almost all the classically offered instances of MR in animal evolution, especially against the evidence of neural plasticity and the differently expanded cerebrums of mammals and birds. In contrast, we argue that some of these classical examples of MR are indeed valid and that Shapiro’s original MCT correction of MRT is the better account of the evolution of consciousness in animal clades. And we still agree that constraints and convergence refute the standard, nearly unconstrained, MRT. (shrink)

This paper deals with a major problem of the early days of the science of palaeontology, the nature and origin of fossils. In 1725, the German physician and academician, Dr Johann Beringer, was deceived into believing that fraudulent, carved stones were true fossils. Despite an extensive analysis, Beringer was not able to fit his ‘fossils’ to any contemporary concept of how fossils originate. The reason for Beringer's inability to classify his stones is explored here. It is argued that the carvings (...) embodied a sixteenth-century, Neoplatonic, concept of fossils, a concept that was outdated in Beringer's time. Beringer chose not to explain his stones rather than to accept the meaning they implied. (shrink)