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Why the Topic of Bioethics in Science Classes?

A New Look at an Old Debate

by Carolyn Csongradi

"Nurture" Is More Influential Than "Nature"

Experiences are written onto the mind, which is essentially a blank slate. We have knowledge of the world because we learn from experiences. "Prior to experience, the human mind is a 'white paper', void of all characters, without any ideas. " Each aspect of behavior is acquired from the environment.(23)

Philosophical discussion

The philosopher Hume thought the mind a blank slate(tabula rasa) on which experience could be written. Hume was preceded by another philosopher, John Locke who was also a contemporary of Isaac Newton. They belonged to a school of thought known as Empiricism which states that knowledge is derived from experiment and observation and were joined by science contemporaries, Sir Francis Bacon and Robert Boyle.(16) Locke thought all knowledge of the world was gathered through sensory experience. This information coul d be manipulated into more complex ideas by reflection and reasoning. He saw the mind as having innate powers of observation, but not of ideas which were to be constructed from sensory input. Hume, expressing the extreme of skepticism, felt nothing was objective, everything was chaotic, connections between impressions were imagined.

Critics observed that this line of thinking could not explain cause and effect in a novel situation unless one was allowed to rely on a multitude of previous experiences. Berkeley, a contemporary of Locke, argued that Locke's logic led to the conclusion that all knowledge ultimately becomes ideas in the mind which may or may not resemble reality. Our perception of nature is a mental experience. Kant, who was familiar with the discoveries of Newton, helped solve this conflict. He argued that while knowledge came from sensory information, we have inherited the ability to categorize sensory information with respect to time, space and causality. A rock thrown at a window will break the glass. The future should look like the past.

The "Natural Law Theory" argued that moral principles could be discovered through careful reflection.(31) Reasoning was needed to counter or balance the natural inclinations of individuals. These laws of nature, rather than the individual customs and preferences, determined what action was "right". While the powers of reason were a part of the mind, principles were not. They remained to be found by observing nature.

Essentially, this is a philosophical discussion about how sensory knowledge is organized by the mind. Do we have an innate ability to manipulate objective sensory information or must this be learned entirely from experience? This difference in opinion is not likely to lead to any resolution of questions concerning the origin of values or moral knowledge nor explain the large body of scientific literature eq uating structural changes in biologic systems with learning.

Neurological studies

In a recent best seller, neurologist Oliver Sacks examined a man, Virgil, who had had cataracts clouding both eyes following an early childhood illness.(37) Earlier, several physicians had examined Virgil's eyes and concluded his retinas had been damaged as well by the same illness and concluded cataract removal would be futile. As an adult Virgil was functionally blind. At age fifty, Virgil was once again examined by a specialist whose opinion differed from earlier recomnnendations. This physician felt Virgil's retinas might have limited function and recommended removing both cataracts. Virgil agreed and thus became a fascinating opportunity for Sacks to study perception and the role of nature in visual learning.

After the surgery, Virgil reported seeing blurred visual images and had little ability to identify what he was seeing. For instance, a face seen wasn't known as a face until touched and he was unable to make sense of facial expressions. His primary route for knowledge of objects continued to be tactile. Over time, he showed little sense of depth perception, having difficulty judging objects in the distance from those which were close. He was as Sacks said, mentally blind.

After struggling for many months to learn to navigate visually, Virgil began to have long periods of spontaneous blurriness which were not observed by his doctor in patients who had had cataracts for a much shorter time. Sacks and the opthamologist concluded Virgil's visual cortex was in neural overload and responded by a sudden shutting down. This process of disconnection has been observed in many different animals when feeling overwhelmed.

In the end, his retinas continued to have the same physical appearance and Virgil's perception continued to deteriorate. Virgil became more blind than he had been befo re his operations, although he experienced rare moments when he could see something accurately. Whether this ultimate loss of vision was related to an intervening bout of a near lethal pneumonia or excess sensory stimulation could not be determined. What is clear is that nurture plays a major role in our ability to make sense of visual stimuli. Seeing is not necessarily "to see". Even if an alternative mode is developed for object identification, this coneptual information does not appear to transfer readily between sensory systems.

Nature and Nurture Continued:

Nature and Nurture Interact in Sequential Stages

Reasoning Processes

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