NETS AND THE NATURALIST

Suppose I come across a lake and I want to find out how many and what sort of fish live in it. I decide to take a boat across and pull along a net to trawl through the water. I set out and sail from one side of the lake to the opposite side, land the net and take out the fish. There are a hundred fish of medium to large size. The next day I repeat the same journey but on this occasion with a different net. Again I land the net and count the fish. In addition to the medium and large ones I find a great number of small fish.

How do I make sense of the results? How is it that there is such a contrast between the two days? I had not mentioned the difference between the nets. The net I used on the first day had a very wide mesh: in the net used on the second day the holes were much smaller.

So the difference between the two catches of fish was a measure less of the number and type of fish in the lake and more of the size of the mesh of the nets.

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Out in the countryside a keen naturalist regularly listens to bird song and keeps a precise tally of the numbers and species of birds in the vicinity. He carries out his count for decades from his youth to old age. Although for many years the number and range of species has stayed much the same, he now is noticing that more and more there is a decrease both in overall numbers and in types of birds. In other similar habitats other naturalists record continued stability in the bird population.

What accounts for this discrepancy? Was there some feature of his particular locality that was the cause? One day the naturalist has a hearing test. A deficiency in his hearing is detected and hearing aids are prescribed and worn. Remarkably, he finds that when he resumes bird watching and recording, the figures he used to note are now restored. Similar number and types of birds as in his earlier days.

During the period when his hearing was impaired, his ears did not register bird song at a high pitch. With the hearing aids, these sounds became audible again. The point? His record making was shaped by the quality of his hearing and his records were partly evidence of the bird population but also partly of his auditory apparatus.

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Questions: To what extent do we perceive the external world as it really is?
To what extent do the limitations of our sense organs determine our perception of the external world?

“We do not see things as they are, we see them as we are.” Anais Nin

“If you always wore blue spectacles, you could be sure of seeing everything blue.” Bertrand Russell

PAYING ATTENTION

When we listen to music — I am thinking of pieces in which several instruments play together, each following its own line: a small wind ensemble, a string quartet, traditional jazz, for example —it is possible to put attention on to one instrument in particular so that it moves to the foreground while the sound of the other instruments recedes a little, still heard but not as prominent. For me this works well if the bass line is singled out.

The impression given is that somehow I have power over my mind and that I can direct its focus, like using a spotlight in a theatre, on one feature of a conscious experience while slightly fading others. I wonder what is going on here. What, to begin with is happening in the brain? The sound waves, the data from all the instruments, continue to stream into the ear as before. But at some point it is as if a dial has been turned to raise the volume of one instrument and another dial turned to lower the other instruments.

I don’t think for a moment that there is a separate me with access to the metaphorical dials. At the level of the brain there must be physical correlation amongst some of those billions of neurons to what is happening at the conscious level. Would a brain scan reveal this correlation? How does it happen?

I suppose that there is a similar process as regards visual experience. I look up now and can see four pictures next to one another and while they all remain within my visual field, one in particular can become my special focus.

Of course, this problem is only one aspect of the much wider one, namely, why there is a conscious experience of hearing or of seeing in the first place since it has no place or explanation within the physical world.

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Another thought on this. I think that this sort of attention shifting is quite different from the process of acclimatisation (there is probably a technical name for this in psychology). What I am referring to is the common experience of ceasing to notice a feature of a familiar environment once one has become accustomed to it: wallpaper, a clock ticking, the sound of a nearby motorway. The examples above feel deliberate, intentional whereas this acclimatisation seems to just happen in due course of its own accord, as it were.