The Origin of the Mammalian Brain

The gradual evolution of mammals. Though mammals are named after their distinctive mammary glands, their neocortex is an equally distinctive trait, and as suggested in discussing the structure of the non-mammalian vertebrate brain, it comes from a reorganization of the thalamus that transfers responsibility for all three subfunctions of the animal behavior guidance system to the forebrain. Since the neocortex derives from the reptilian DVR, mammals could not evolve until reptiles had evolved.

This reorganization had be tried out soon after reptiles, however, rather than later, for it is such a radical random variation that only the most primitive reptiles could continue to function. By the time reptiles had acquired as much power as possible for animals of their kind, their DVR would have become so essential to so many different kinds of behavior that such a radical random variation would probably have been fatal.

This obstacle is most obvious in the avian brain, where the DVR/striatum is divided by well-defined laminas into many separate regions serving special functions, such as controlling pecking and generating bird songs. Each part of the telencephalon generates behavior separately, by its influence on the midbrain and hindbrain. It is not that the advantages of complete circuits through the forebrain are entirely overlooked in birds. It does occur, but in a more limited way. As we have seen, birds evolved a mammal-like memory; the "visual Wulst" is part of a mechanism that resembles the mammalian memory circuit.[1] But the avian brain lacks spatial imagination, because without a behavior generator that operates on a somatotopic representation of the body, it cannot acquire behavioral schemata from experience with the structure of space, but must rely on mechanisms supplied by the primary structure. Nor does avian memory include any sensory modalities beyond vision. It appears that the DVR-striatal circuit had become too complex by the time birds evolved for the DVR to migrate to the dorsal cortex and become a neocortex. Thus, birds have only a memory which is, at most, an advanced telesensory memory, that is, using a one-dimensional series of stimulus-response connections to get around in space as part of an instinctive routine for controlling specific conditions. But the visual Wulst is all birds need to record locomotor commands in relation to visual images and calculate directions and distances to unseen objects, for that enables them to find their way back to their nest, patrol at territory, and migrate with the seasons using visible landmarks.

Fossil evidence shows that mammals did evolve from primitive reptiles as our theory predicts. The last common ancestor of mammals and extant reptiles was 300 million years ago, about the time that reptiles first evolved. But there is still a problem with our explanation of mammalian evolution, which accidentalists often use to argue that mammals are not inherently superior, but merely different from, non-mammalian vertebrates: if mammals are more powerful, why were they dominated by dinosaurs for nearly 150 million years before the radiation of mammals? It seems that there would never have been a radiation of mammals, if it had not been for the impact of an asteroid. To answer this objection, we must consider the course of mammalian evolution.

Earth was dominated by mammal-like reptiles before dinosaurs evolved (about 225 million years ago). Mammal-like reptiles (therapsids) had tucked-in elbows and legs positioned more directly under their bodies, so they were better able to scamper over land than reptiles and probably fed on them. They used the energy, not only to stand upright, but also to supply a warm-blooded metabolism. Although some therapsids were as large as wolves, they were largely eclipsed by two-legged predatory dinosaurs about 225 million years ago.

But mammals continued to evolve during the age of dinosaurs. About 190 million years ago, mammal-like reptiles gave rise to a branch of primitive mammals (prototheria) which seem to have living descendants, the monotremes: the duckbilled platypus and the spiny anteater.

To judge by them, primitive mammals were warm-blooded and hairy. Although the platypus is still an egg-laying animals, it nurses its hatchlings and cares for its young, which is a radical innovation, considering that most reptiles have so little concern for their offspring that they sometimes eat their hatchlings when they come across them hungry. And monotremes have the mammalian neocortex (although it is not differentiated into as many areas and lacks the corpus callosum, the massive bundle of fibers that links the two hemispheres of neocortex in true mammals).

Later during the age of dinosaurs (about 135 million years ago), marsupials (metatheria) branched off from true mammals (eutheria), indicating that mammals had evolved all the basic traits that distinguish them from non-mammals during the reign of the dinosaurs, including live birth. But that did not enable mammals to replace dinosaurs in their energy-rich ecological niches, even though prototheria had about 55 million years and metatheria and eutheria had 70 million years to do so.

It seems, therefore, that what finally brought the age of dinosaurs to an end was not the inherently greater power of animals from a later stage of evolution, but an accident — the impact of a giant meteor or asteroid about 65 million years ago. The age of mammals might never have begun, if it depended only on the greater power of a higher level of part-whole complexity in the brain.

This accidentalist argument against the inherent superiority of mammals can, however, be answered when evolution is explained by reproductive causation. Incumbency in an ecological niche has an obvious advantage, and to deny that evolution is merely a matter of tracking changes in the environment is not to deny that catastrophic environmental change shakes out the natural kinds best suited for the more energy-rich ecological niches by forcing incumbent species from earlier stages to compete on a more equal footing with inherently more powerful kinds of living objects. This is the role of environmental change in the case of mammalian evolution. Indeed, it suggests that the question should be turned around. If mammals were not inherently superior, then how did they manage to displace dinosaurs when a catastrophic change did finally occur?

The mammalian nervous system evolved during the age of dinosaurs, and the more profound question is how mammals could evolve at all in competition with the incumbent dinosaurs. The answer seems to be that mammals occupied a more demanding ecological niche, where dinosaurs could not compete. And what made that possible was an animal system of representation with spatial imagination.

The first mammals were small, rodent-like animals that apparently foraged (for insects) at night, when dinosaurs could not see them or, perhaps, were immobilized by the cold. Sight was not their major telesensory modality, if we judge by the relative smallness of their eyes. Instead, they had long snouts and external ears, which suggests they had highly developed olfaction and hearing, both of which can be used just as well in the dark. Since all the telesensory modalities contribute in the same way to spatial memory in the subjective animal system of representation,[2] mammals could get around in the dark at least as well as reptiles do with light using only touch, hearing, and olfaction. Touch (including whiskers) would enable them to detect nearby objects, and using their map of the territory, they could get about well enough by keeping track of how far they move in each direction. Their spatial imagination would give them an experience of moving among salient objects in their territory much like the "virtual reality" generated by computers. Hearing (and olfaction) would tell them about objects at a distance, both their location and kind. And olfaction would enable them to recognize particular objects, confirming locations in their map. Thus, mammals could get around in their territory just as well when they could not see.

The subjective animal system of representation also explains parental behavior, including nursing, by which mammals are named. We have seen how the structural cause for various kinds of behavior, that is, the behavior schemata for setting up and using both local images and maps of the territory, are acquired from experience with the structure of space in moving around among objects in 3-D space, rather than from the biological behavior guidance system. Thus, mammalian young are simply not able to acquire energy in the ecological niches they inherit from their parents until they have matured enough to construct local images and link them together in their own maps of the relations of objects in space, that is, as a World Image. Just as birds must care for their offspring before they can fly and acquire energy for themselves, so mammals must care for their offspring until experience in locomotion enables them to develop a spatial imagination. Thus, mammillary glands (in monotremes) and live birth (in marsupials) are probably just an elaboration of the nurturing behavior required by the subjective animal system of representation (as indicated by the early evolution of the neocortex).

One hundred fifty million years is surely long enough to make the subjective animal system as effective as possible in representing the world as a world of objects in space, and so, when the impact of an asteroid caused clouds that changed the climate, destroying rain forests and rich vegetation over much of Earth, mammals were better able to adapt to the new conditions than dinosaurs.

As telesensory animals, dinosaurs had to rely on more or less complex fixed action patterns that enabled them to construct maps, acquire energy, and attain other goals in the previous, lush environment, and reproductive causation was the only way to adapt those complex instincts to radically new conditions.

Mammals, however, had the advantage of spatial imagination; when a desire was strong, they had the capacity to predict what would happen if they moved their bodies in space before they acted, so that "hypotheses die[d] in their stead." And with a behavior generator that operates on a body image to send separate motor commands to all parts of the body, mammals were able to generate new kinds of behavior by putting local motor commands together in new ways and, thus, could learn new kinds of behavior by trial and error within a single lifetime.

Hence, mammals had a distinct advantage when the environmental catastrophe put them on a more equal footing with dinosaurs. Dinosaurs were, of course, already much larger animals, and so it is not surprising that it took many generations before the mammalian population increase and the adaptation of their bodies to the new ecological niches deprived dinosaurs of their sources of energy.

Dinosaurs may have continued to exist for thousands of years after the impact of the asteroid, but that would not be long enough for them to evolve the new instincts needed to exclude mammals from their high energy ecological niches. Or to put it the other way, if there had been no mammals, dinosaurs would not have had to compete for energy, and they would probably have adapted to the new environment in the end.

Therefore, although the “radiation” of mammals was occasioned by the extinction of dinosaurs some 65 million years ago, the basic cause was not that dinosaurs were selectively wiped out by an asteroid, leaving mammals to inherit the earth. The asteroid merely changed all the sources of usable energy tapped by animals of both kinds so radically that mammals were able to replace dinosaurs in the new ecological niches because of the inherent superiority of the mammalian brain, with a neocortex, in which a spatial imagination made them better able to acquire usable energy.

It may still seem that the evolution of mammals is not inevitable, because evolution would not proceed through the whole series of possible stages if it were not for such catastrophic events shaking things up enough to make subsequent stages of inherently more powerful primary structures inevitable.

However, it is not an accident that radical changes occur in all the ecological niches at once. It is inevitable on planets like ours. For example, if asteroid bombardment is a result of perturbations in an Oort cloud of debris farther out from the star than where planets can form, as has been suggested, it would probably happen on any planet where life evolves at all. And there are other sources of asteroids. Thus, catastrophic events are normal on planets that orbit stars, and the dependence of evolution on them would not make the stages any less inevitable.

Furthermore, to assume that the overall course of evolution depends on occasional catastrophes is not to suppose that natural selection is caused, after all, by externally originating changes in the environment. What makes it seem that evolution is merely tracking externally caused changes in the environment is thinking of evolution as if only a single species were involved. But when evolution is explained by its ontological causes, we see that many species evolve during each stage of evolution, and from that broader perspective, we can see that the main effect of catastrophic changes in the overall course of evolution is to shake things up so that inherently more powerful organisms are not stymied by the accumulation of accidents. It makes evolutionary stages inevitable. Catastrophes cause mass extinction of species, and the “adaptations” that do take place are the increasing power by which the gradual evolution of inherently superior organisms taps usable energy in all parts of the environment, such as the radiation of mammals after the extinction of the dinosaurs.

The mammals’ higher level of neurological organization does, therefore, account for their gradual evolution, both before and after the catastrophe with which the Age of Mammals began some 65 million years ago. They could occupy more demanding ecological niches alongside dinosaurs before the catastrophic change, and then, once they could compete on a more equal footing, there was a bush-like radiations of mammals. After overcoming the dinosaur's advantage as incumbents in ecological niches, reproductive causation would adapt mammals to acquire free energy from all possible sources in all possible habitats, from jungles and forests to meadows and deserts, and from oceans and rivers to caves and polar ice caps. In short, from our ontological foundation, we can predict not only the revolutionary change with which the age of mammals began, but also the radiation of mammals. It eventually occurs on any planet where life evolves at all.

There is, however, a puzzle. If mammals are inherently more powerful, why didn’t they also displace the birds? Mammals can evolve the capacity to fly. Bats are proof of that. But bird continue to occupy almost all the other high-energy ecological niches open to flying animals.

Are birds incumbents in ecological niches that require a more severe environmental catastrophe before they can be displaced?

Or do ecological niches that depend on flying require only a one-dimensional visual memory for chains of stimulus-response connections that are imbedded in instinctive routines? Since bats fly at night and in caves, where birds usually cannot fly, are they merely taking advantage of their subjective animal system of representation to occupy an ecological niche that is not open to birds? That is, does a vision-based memory without spatial imagination make telesensory animals so powerful in ecological niches that require locomotion by flying that animals with a multi-modal memory and spatial imagination have no advantage — at least, none great enough to compensate for the greater costs of developing a nervous system with a higher level of part-whole complexity?

The unity of consciousness. In Properties, the nature of consciousness, that is, the existence of phenomenal properties, was explained by showing that material substances must have an intrinsic aspect to their essential natures. Spatiomaterialism implies that elementary bits of matter have intrinsic natures. That is enough to explain simple sensory qualia. But that is not a full explanation of the nature of consciousness, because it does not show that intrinsic natures can explain the kinds of phenomenal properties we have (as we noted when explaining the nature of the necessary connection that solves the contemporary naturalists problem of mind in Properties: Ontological explanation of the necessary connection between physical and phenomenal properties).

What reflection (or introspection) reveals are complex phenomenal properties with qualia of many different kinds all appearing to the subject at once. But spatiomaterialism entails a kind of panpsychism, in which only the most elementary bits of matter must have intrinsic natures. Since the intrinsic natures of elemental bits of matter are presumably only proto-phenomenal properties, it remains to explain what Nagel calls the “unity of consciousness.”

But how can the intrinsic natures of the most elementary physical objects account for complex phenomenal properties? It cannot come from how simpler physical objects are related spatially as parts of more complex physical objects, for there is no reason to believe that a composite physical object, like the brain, will have an intrinsic nature as a whole. The parts of the brain are outside one another in space, and the unity of the whole brain depends on the extrinsic natures of the parts, since what holds the parts together and enables them to interact are the forces that they exert on one another. Thus, it may seem that spatiomaterialism cannot explain why the subject as a whole has phenomenal properties in which qualia are combined in such rich appearances as those that occur in perception.

The nature of complex phenomenal properties. There is one way that spatiomaterialism can explain phenomenal properties (and only one way, as far as I can see). In order to see how it works, we must take into account both the basic nature of matter and the structure of the mammalian brain.

The nature of matter. Spatiomaterialism takes “matter” to refer to all the forms of mass and energy whose quantities are counted in the principle of the conservation of mass and energy, including all the kinds of particular entities to which the basic laws of physics refer. Quantum field theory distinguishes two different kinds of basic particles, fermions and bosons. They have opposite natures in a relevant way.

Fermions and bosons have opposite relationships to other particles of the same kind.

Particles such as electrons, quarks, and nucleons are fermions. With “½ spin” (or a multiple of it), they exclude other objects of the same kind from occupying the same location or quantum state (except for one other particle with the opposite orientation of spin).

Photons, with a spin of 1, are the prime example of bosons (though bosons can also have spins of 0 or 2). Bosons do not exclude one another from occupying the same quantum states, and so there is no limit to the number of bosons of any kind that can have the same location.

Fermions and bosons have opposite relationships to space.

Fermions (with mass) are most like ordinary physical objects, for they are point-like particles (or spatial complexes of them) which are able to be at rest is space.

Photons are interacting electric and magnetic forces, and by contrast to fermions, they seem to be spread out in space, for even though they exist only as whole (quantum) units, they move through space at the velocity of light. (A boson-like nature is also found in the electric forces by which fermions interact with one another, but as we have seen this form of matter is spread out as a field and the way it coincides with space means that its quantity is included in the total rest masses of the objects exerting the forces.)

According to spatiomaterialism, all the simplest bits of matter mentioned by physics must have intrinsic natures. But since bits of matter can occupy more than just a single point in space, there is no reason to deny that their intrinsic natures can have spatial structures. That suggests that, since photons seem to be units spread out in space, they could have intrinsic natures with complex spatial structures, even if fermions do not.

The basic nature of photons opens up, therefore, the possibility of an explanation of complex phenomenal properties by intrinsic natures. But we are still far from seeing how it works.

To be sure, the photon-like nature of the electromagnetic forces binding electrons to nuclei in atoms and atoms to one another in molecules may also give each of them an intrinsic nature as a composite whole. But their intrinsic natures extend only as far as the objects they bind, and since that is not far enough to include whole brains, their intrinsic natures can hardly account for phenomenal properties. To see how it is possible, we must consider the structure of the brain.

The structure of the mammalian brain. The basic structure of the mammalian forebrain involves a massive projection of neurons from the thalamus to all parts of the neocortex (and back), and as we have seen, the brain’s main functions are all served by its massively parallel information processing. Different nuclei in the thalamus project to distinct regions of neocortex, and there are three complete circuits from the neocortex through other structures back to the thalamus and neocortex. Information is being processed within those circuits in two-dimensional arrays of neurons (as shown by association fibers that connect them topographically). Many such 2-D arrays in the posterior neocortex are clearly processing sensory information about the same objects in space at the same time, and many other 2-D arrays in the anterior neocortex are processing both sensory input from and motor output to the body at the same time. Finally, a 40-75 hertz pattern of firing set up by the thalamus apparently synchronizes activity in all areas of the neocortex, integrating the three complete circuits.

Crick and Koch (1990) defend the hypothesis that the 40-75 hertz synchronization of the firing of thalamic neurons to the neocortex is the foundation of consciousness. But they do not explain how it gives rise to phenomenal properties. Given the spatiomaterialist explanation of intrinsic natures, however, phenomenal properties could be explained as the intrinsic natures of the electromagnetic waves set up by the synchronized firing of neurons throughout the thalamic projection to the neocortex.

Electromagnetic waves are, of course, photons, one of the basic forms of matter contained by space, and since they are generated by the acceleration of charged particles, they are clearly being generated by brain activity. A neuron carries signals from one place to another by an “action potential” which propagates along its axon as ions of one kind at each successive point rush into the neuron and then ions of another kind flow back out. The acceleration of such ions makes the synchronized firing of thalamic neurons act like an antenna, generating a complex electromagnetic wave.

Since electromagnetic waves, being composed of elemental photons, are a form of matter whose spread-out nature could give their intrinsic nature a spatial structure, there is an elemental bit of matter generated by active brains whose intrinsic nature could have enough spatial structure to account for complex phenomenal properties. It is the electromagnetic energy being given off as a series of complex photons by a human brain that is not asleep.

This is all the more plausible when we consider that the brain, despite making up only a few percent of body weight, accounts for nearly 20% of the body’s total energy consumption.

In order to be sure that the intrinsic nature of the energy being given off by the brain accounts for phenomenal properties, more would have to be known about the complex geometrical structure of the photons generated by the synchronized firing of neurons in the thalamic projection to the neocortex. Indeed, it is likely that much more remains to be discovered about the basic nature of light than physicists suppose. But that is beyond the scope of this argument. But for our purposes, it is enough to see how this ontological explanation of the nature of properties, this ontological explanation of the truth of physics, and this ontological explanation of the structure of the subjective animal system of representation combine to provide an explanation of the kinds of phenomenal properties that beings like us have.

Complex phenomenal properties. To make it plausible that what is relevant is the energy being given off by the thalamic projection to the neocortex, let me suggest how it would explain what Nagel called the “unity of consciousness.”

The unity of consciousness can be seen in perception, for at any moment, many particular qualia from several sensory modalities all appear to be located in and around one’s body in what can only be called phenomenal space. Objects with colored surfaces appear to have locations around the body, and they often make noises that seem to come from their locations. Color and tactile qualia also seem to be located in the body, and as it moves, one can feel objects at certain locations in space outside the body. The spatial coherence of the perceptual appearance is so complete that many philosophers who are otherwise critical realists still assume that the space in which sensory qualia appear to be located is the same space in which the objects (and body) they represent actually exist, that is, the the qualia are somehow projected outside the brain. But since spatial aspects of perception are just as much part of phenomenal properties as the sensory qualia themselves, we must distinguish phenomenal from real space.

There are at least three reasons to believe that complex phenomenal properties like these can be explained by the intrinsic natures of the photons generated by the thalamic projection to the cortex.

First, as the anatomy of the brain suggests, all the information processing of sensory input leading to motor output that is going on in the brain is registered in the firing of neurons in the thalamic projection to the neocortex and, thus, in the electromagnetic waves it generates.

There are three way in which the projection from the thalamus to the neocortex projects back to the thalamus, completing a circuit. All areas of neocortex have association fibers that project to the temporal lobe near the hippocampus and thereby connect (via the fornix) with the anterior nucleus, which projects back to the cingulate gyrus of the neocortex. All areas of the neocortex also project to the corpus striatum and thereby connect through the ventral anterior and ventral lateral thalamic nuclei back to the frontal neocortex. Also located in the temporal lobe is the amygdala which connects by way of the dorsomedian nucleus of the thalamus back to the frontal regions of the neocortex. The first circuit clearly mediates the formation of long term memory; the second generates behavior in relation to objects in space; and the third attaches desires to objects by arousing disposition to behave toward them in certain ways. Thus, the thalamo-cortical projection seems to mediate all the main brain functions.

But since the neocortex is one of the mechanisms involved in all three complete circuits which realize the subsystems of the subjective animal behavior guidance system in mammals, its neurons (including association fibers between 2-D regions of neocortex) may also contribute to the photons whose intrinsic nature constitutes phenomenal properties.

Second, it seems possible to explain the spatial coherence of complex phenomenal properties, at least, in principle. It is likely that simple sensory qualia are parts of the electromagnetic wave generated by thalamic neurons projecting sensory input to primary sensory areas of neocortex, for when they fire, they fire at an unusually high rate. The appearance of green at a certain location in the visual field, for example, is presumably due to the rapid firing of certain neurons in the 2-D array projecting from the lateral geniculate body of the thalamus to the visual (striate) cortex.

Given how colors vary with different combinations of the intensity of opponent colors (red-green, blue-yellow, and black-white), the relevant wave patterns presumably depend on the combination of neurons projecting to each region of the visual cortex that originate at different lamina of the lateral geniculate body and fire at different synchronized rates.

Since all the 2-D arrays processing visual input in the neocortex are connected to one another topographically by association fibers, the neurons in each that represent the same parts of an object’s visual appearance are presumably synchronized throughout the neocortex. That ties higher-level processing to the corresponding neurons responsible for sensory qualia and integrates all their effects on the electromagnetic wave, so that its spatial structure could contain all the information the brain uses for guiding behavior.

The same is true of the various 2-D arrays representing the body, and given how those body representations are connected with visual and other sensory 2-D arrays, it is not implausible to suppose that the result is a series of photons generated by the entire thalamo-cortical projection whose intrinsic natures are spatially coherent. That could be why sensory qualia seem to have locations in phenomenal space.

The fainter qualia of all sensory modalities that occur in memory and imagination could likewise be explained as due to centrally-generated firings of neurons that otherwise occur only in later stages of the process of sensory analysis.

Finally, locating the phenomenal property in nature as the intrinsic nature of the electromagnetic wave generated by the thalamic projection to the neocortex would explain the phenomenon of blindsight. When the projection from the thalamus to the visual cortex is damaged and subjects claim not to have any visual experience, they are still able to answer questions about the locations and shapes of objects and to take them into account in their behavior. The lack of visual qualia is what would be expected on this theory, since what is missing is the relevant thalamo-cortical projection. And the residual visual discrimination could be explained by the visual processing still going on outside the forebrain in the superior colliculus (the midbrain nucleus that was responsible for using visual input to guide behavior in reptiles) and its limited projection to a region of the thalamus (the pulvinar) that projects to secondary areas of the visual neocortex.

Ontological philosophy offers, therefore, a plausible explanation of the unity of consciousness. The physical properties of the photons generated by the brain suggest that they are a form of matter whose intrinsic natures could be the complex phenomenal properties we have. What makes it possible to solve the explanatory problem that Nagel finds in panpsychism is the recognition that space is a substance. Coinciding with space explains not only why bits of matter have spatial relations to one another, but also how they can coincide with whole regions of space. Thus, it shows how their intrinsic natures could have complex spatial structures, and that makes it possible to see how photons can have a spatial structure that depends on activity throughout the brain, accounting for the complex structure of the phenomenal properties that we are calling "consciousness."

An attractive feature of this explanation is that it suggests a research project. Complex phenomenal properties might be explained in detail by working out precisely the geometry of the electromagnetic waves generated by ions being accelerated in and out of cylindrical axons of certain neurons in each of many 2-D arrays of the massive, basically parallel projection from the thalamus to the neocortex as they fire simultaneously 40-75 time each second.

Furthermore, if the synchronization of firing cycles throughout the thalamus is required for the coherence of the complex phenomenal property, it can settle a question about the unity of consciousness in split-brain patients. In split-brain patients, the massive corpus callosum which connects the two hemispheres of the brain is cut (usually in order to prevent epileptic seizures). Whether they have one or two minds, that is, one or two unified appearances made of sensory qualia in phenomena space, would depend on whether their thalamic nuclei are still synchronizing the firings of neurons in both hemispheres. That is something that could be determined empirically.

Implications. Even without carrying out those research projects, however, this explanation of phenomenal properties, if true, has consequences that are relevant to the positions mentioned in the discussion of consciousness in Properties.

Epiphenomenalism. Thomas Huxley likened epiphenomenal properties to the whistle or steam giving off by a steam locomotive, because they have no causal role in propelling the train. If we take “epiphenomenal” to mean being an effect of physical properties without having any effects in turn on physical properties, the spatiomaterialist explanation implies that phenomenal properties are epiphenomenal in two different ways.

First, as we have seen, phenomenal properties are epiphenomenal relative to physical properties as such, because they are kinds of intrinsic natures that are caused to exist as a result of extrinsic natures of the bits of matter involved. That is, the spatial structures of the photons that account for the complexity of the relevant phenomenal properties are also aspects of the extrinsic natures of those bits of matter, because those spatial structures can in principle, be explained by physics.

Second, since the relevant bits of matter are the electromagnetic waves, they are just a form of energy being dissipated by the brain as a by-product of its activity, and so those bits of matter themselves are epiphenomenal relative to the physical properties of the brain itself. Those photons are effects of the brain’s activity that do not, in turn, affect its states. (What happens in the brain is caused by the synapses made by the neurons that fire, not by the photons generated by their action potentials.)

Thus, phenomenal properties depend on two “causal” connections, the efficient cause by which the brain activity causes electromagnetic waves, and the ontological cause linking the extrinsic natures of the electromagnetic waves to their intrinsic natures.

Robot consciousness. Given that phenomenal properties are the intrinsic natures of the brains’ electromagnetic waves, it is not very likely that robots whose behavior is guided by computers made of silicon chips will be conscious in the way we are. Though they will also generate electromagnetic waves and will, therefore, have some intrinsic nature or other, it is unlikely that their phenomenal properties will be anything like our own.

Their information processing is basically serial, rather than parallel, and since silicon chips have, in any case, a completely different geometry from brains, the rising and falling electric and magnetic forces in the “wires” of silicon chips will generate photons with a completely different geometry in space and time.

Nor can such robots experience sensory qualia as located in space, if what is responsible for the unity of consciousness is, as suggested above, the synchronized processing of representations of the same objects in different, interconnected 2-D arrays of neurons projecting to the neocortex.

Ontological philosophy also implies, therefore, that Chalmers (1996, Chapter 7) was mistaken to believe that phenomenal properties are caused by functional, rather than by physical properties. His argument was the implausibility of qualia slowly “fading” out as parts of the brain were replaced by functionally equivalent silicon circuits, and the implausibility of color qualia “dancing” from one kind to another (or to none at all) as the processing of part of the visual array was switched between brain mechanisms and silicon chips. Implausible though it may seem to Chalmers, that is what must happen, if phenomenal properties are the intrinsic natures of electromagnetic waves generated by the processing. But at this point, his fading qualia and dancing qualia arguments show, not the implausibility of phenomenal properties being caused by physical properties, but rather the perils of giving up the empirical method (as in empirical ontology) in favor of philosophical arguments from plausibility (where functions and other properties seem more basic than substances).

Knowledge of phenomenal properties. Ontological philosophy makes consciousness a part of natural science without abandoning the empirical method in favor of the traditional epistemological approach to philosophy. But since it implies that phenomenal properties are epiphenomenal, they have no effects on what happens in the natural world, and thus it may seem that phenomenal properties cannot be known even privately. How can subjects know about their phenomenal properties, if those properties are never causes of what they say about them?

That phenomenological properties do cause beliefs about them is apparently what Descartes assumed in arguing, "I think, therefore I am." In order for thinking to show the subject that he exists, the subject must know that he is thinking when he is thinking, and Descartes seems to take it for granted that the subject knows that he is thinking because the appearance of the ideas in the mind makes the subject aware of what is happening in his mind. (That is the "illusion involved in reflection" that Descartes still does not see through after he sees through the "illusion involved in perception" and becomes a critical realist.)

Nor would this problem arise if phenomenal properties played the kind of causal role mediating between sensory input and behavioral output that Searle (1992, 1995, and 1997) ascribes to pain, that is, being an effect of, say, a pinch, which in turn causes one to say “Ouch!” In that case, phenomenal properties would be effects of sensory input, and they would be the causes of reports about them. But causal emergentism of that sort is incompatible with spatiomaterialism.

Given this explanation of the mammalian brain and consciousness, however, it is not necessary for phenomenal properties to be efficient causes of behavior in order for them to be private objects of knowledge.

First, to see how we can know that we have phenomenal properties, we need only recognize that such knowledge comes from (and arose historically in modern philosophy from) accepting critical realism, that is, distinguishing phenomenal properties from physical properties. It is like something to be a human being, as we have seen, because the functioning brain involves a bit of matter whose intrinsic nature registers the activity of the entire brain. We assume, as naive realists, that the world as it appears to us in perception is the real world, with qualia located in objects that are assumed to exist independently of us in space. But when we recognize that perception is a physical process in which the objects stimulate our sensory organs, thereby giving rise to brain states representing them, we can come to see that our sensory qualia are parts of us, as the subject who is perceiving, not parts of the independently existing objects. And if we follow this argument to its conclusion, we also come to recognize that the space in which sensory qualia seem to be located is merely phenomenal and, thus, distinct from the space in which the physical objects actually exist. Critical realism about perception makes it clear that objects with physical properties in real space exist somehow “beyond” the complex phenomenal properties we have, so that we discover that we have phenomenal properties by recognizing that physical properties do not appear to us at all, except indirectly through phenomenal properties.

These spatial configurations of sensory qualia are not the only complex phenomenal properties we have, but they are an important variety, and the failure to give up naive realism about space in favor of critical realism about space is the source of much confusion about the nature of consciousness.

Thus, second, there is no problem explaining how it is possible for subjects to pick out particular qualia included in the structures of their phenomenal properties. The phenomenal properties involved in perception are configurations of sensory qualia in phenomenal space, and particular qualia can be picked out in the same way as the objects in real space that they represent, for once we recognize the difference between physical and phenomenal properties, it is one and the same brain capacity being understood in two different ways. We can take our reference to the green apple on the table to be a reference either to the physical object in real space or to a part of the appearance that the world has to us as we perceive the world.

Finally, there is no problem explaining how we know about the kinds of particular sensory qualia that are picked out that way, for once again, it is just to make the same discrimination that we make in describing the properties of physical objects in real space together with the recognition that there is a difference between physical and phenomenal properties. When I call the cup green, I am ordinarily understood as referring to a physical property of the cup (its disposition to cause a certain kind of experience in us). But when I distinguish the phenomenal property from the physical property, I can also identify the kind of qualia representing the physical property. And there is a kind of incorrigibility to the belief about the kind of particular sensory qualia that does not hold for the physical property, for what is meant by the kind of sensory qualia is how it appears to the subject and that is something that is known ostensively in the phenomenal property.

Ontological philosophy, therefore, makes a natural science of consciousness possible. Though we know about our own phenomenal properties in a unique and private way, we can know that others have them. If other brains generate the same kinds of electromagnetic waves as ours, we can know from what experience is like for us, what it is like for them.

But traditional epistemological philosophy will not survive this change, for it makes even the starting point of modern philosophers, like Descartes, part of the essential nature of a world that is explained ontologically. That is, what will make a natural science of consciousness possible is that there will no longer be any difference between empirical science and philosophy when philosophy takes empirical ontology as its foundation (and science recognizes ontology as a more basic branch than physics). But this is to get ahead of ourselves, for that is how ontological philosophy completes the tenth stage of evolution.

To Manipulative Animals 


[1] In the avian brain, the dorsal cortex contains a detailed visual image called the "visual Wulst" which controls locomotion by its own, direct motor output. It is part of a memory map that uses visual input relayed by the thalamus directly from the retina to the dorsal cortex. And as part of the dorsal cortex, the Wulst connects through the medial cortex/hippocampus and fornix back to the mammillary body in the hypothalamus. But instead of merely influencing the midbrain and motor output, as in other non-mammals, the mammillary body relays a signal, by way of the thalamus, back to the Wulst in the telencephalon. This is a complete circuit, resembling the mammalian memory mechanism, and it is apparently used to construct a memory map for guiding locomotion. Assuming that it works the same way as in mammals, the Wulst can use a one-dimensional chain of stimulus-response connections as a map to guide locomotion without involving the rest of the circuit (hippocampus, fornix and mammillary body). But vision is the only sensory modality involved, and judging by the neurological mechanisms, it cannot use its memory map as a locomotor imagination.

[2] Although olfaction contributes to mammalian memory in the same way, this telesensory input is still analyzed in the olfactory bulb, rather than the neocortex, and thus, images of odors cannot be called up in imagination in the same way as visual and auditory images.