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... Science Frontiers ONLINE No. 114: Nov-Dec 1997 Issue Contents Other pages Home Page Science Frontiers Online All Issues This Issue Sourcebook Project Sourcebook Subjects Complexity And Mount Improbable In principle, the combination of random mutation and natural selection can account for any level of biological complexity you wish to have explained. R. Dawkins' Mount Improbable is never too high to scale with this Darwinistic mechanism -- if given enough time, of course. At times though, we have to wonder if there is not a cog railway or something similar to aid organisms as they ascend this Mount. Such thoughts arose when reading C. Koch's Nature article on neurons and their networks. Neurons are cells with three principal components: the cell body, the axons, and the dendrites. These cells and the networks underlie all of our perceptions, actions, and memories. The ways in which they store and process information has turned out to be much more complex and dynamic than previously supposed. Neural networks are so intricate that Koch was impelled to conclude his review of current research with this paragraph: "As always, we are left with a feeling of awe for the amazing complexity found in nature. Loops within loops across many temporal and spatial scales. And one has the distinct feeling that we have not yet revealed every layer of the onion. Computation can also be implemented biochemically -- raising the fascinating possibility that the elaborate regulatory network of proteins, second messengers and other signalling molecules in the neuron carry out specific computations not only at the cellular but also at the molecular level. ...
Terms matched: 1 - Score: 55 - 15 May 2017 - URL: /sf114/sf114p05.htm
... drift. Extremely nasty things are being said about a handful of heretics who attack this position. "One leading dissident, UC Berkeley molecular biologist Peter H. Duesberg, believes that HIV is not the cause of AIDS -- at least not the sole cause. "He thinks the virus may be an opportunistic organism that found a willing host in the AIDS patient who became sick from something else. That is, he believes HIV is the result of the disease, not the cause. Duesberg thinks the cause of AIDS has more to do with the life style of most of the AIDS patients, but he admits that he doesn't know exactly what." Duesberg points out that three things must be true before a microorganism can be blamed for causing a disease. These are called Koch's Postulates, after R. Koch, who formulated them a century ago: Every patient who has the disease must also harbor the suspected microorganism. Some AIDS sufferers do not have the AIDS virus, although it is debated whether as many as half don't or very few don't . The microorganism must cause the disease when injected into research animals -- primates for example. The AIDS virus does not; although some other diseases, such as small pox, do not affect other animals either. The suspect microorganism must be isolated from the patient and grown in a culture. Duesberg claims that HIV definitely fails the first two Koch tests. (Shurkin, Joel N.; "The AIDS Debate: Another View," Los Angeles Times, January 18, 1988 ...
Terms matched: 1 - Score: 42 - 15 May 2017 - URL: /sf057/sf057b08.htm
... being aware of the stimulus and physical response. Normal people experience this in dancing, fencing, etc. Extreme examples include sleepwalkers who can even drive cars and carry out other complex actions without remembering what they have done! Of course, sleepwalking is not a normal condition; nevertheless, rigorous experiments demonstrate that normal people will respond to scary pictures of snakes and spiders even though they are not consciously aware of them. The zombie agent is acting autonomously. Zombie agents are characterized as on-line systems that act at speeds that far outpace conscious reactions. Since the zombie agents incorporated in our unconsciousness work so well, why did consciousness ever evolve? Conscious actions take milliseconds longer to calculate and activate. Consciousness would, therefore, seem to be a bad evolutionary gambit. But, C. Koch and F. Crick may have an answer. They speculate that: It may be because consciousness allows the system to plan future actions, opening up a potentially infinite behavioural repertoire and making explicit memory possible. (Koch, Christof, and Crick, Francis; "The Zombie Within," Nature, 411:893, 2001.) Questions. Could our zombie agents, primitive though they may be, be the source of those flashes of genius that appear out of nowhere, or perhaps that "dreamwork" from which solutions to problems appear fully formed upon wakening? The quotation from the Nature article presumes that consciousness does have survival value, else it would not have evolved. What sort of highly innovative genetic changes would lead to such a remarkable brain function? Did consciousness evolve in ...
Terms matched: 1 - Score: 25 - 15 May 2017 - URL: /sf138/sf138p11.htm
