## Carving up the world with science

In previous posts, I have discussed how we carve up the world, and how that carving up is what allows us to express true statements about the world.  Science also expresses true statements about the world.  In this post I will discuss how that relates to carving up.

Yes, science also carves up the world in its own way.  And it does that in order to be able to make true statements about the world.  So the basic idea is the same.  But the method is very different.

### Which science

Unsurprisingly, different sciences carve up the world in different ways.  Biology is concerned with living organisms.  So it wants to carve up the world into organisms, and then to further carve up those organisms into organs, cells, proteins, genes, etc.  At a larger scale, it wants to look at populations of organism.

In this post, I shall mainly be looking at how physics carves up the world.  That’s partly because the physics way of carving is most different from our ordinary way of carving.  And, additionally, all sciences borrow from physics, at least to some extent.

### Measuring

Take a look at a ruler, such as we use for measuring length.  I have a ruler in front of me know, as I write this.

The ruler that I am looking at has major graduation marks at every centimeter, and minor marks at every tenth of a centimeter.  (It also has graduation marks in inches at the other edge of the ruler).

If I want to measure the length of an object, I line the ruler up against that object.  Then, in effect, I use those graduation marks on the ruler to divide up (or carve up) the object that I am measuring.  And if I want to assign names to those parts, I can use the calibration numbers on the ruler.  For example, I might use “17.3 cm” for one of those small parts into which I have mentally divided the object that I am measuring.

The construction of a ruler is, in principle, quite mathematical.  We start with a standard definition of the meter.  And then the methods of Euclidean geometry can be used to divide the meter into smaller parts (centimeters, millimeters, etc).  It is a standard exercise in Euclidean geometry, to divide a line segment into a number of equal parts.

We do something similar for other types of carving up.  We use a clock to carve up time (or measure time).  We use a thermometer to carve up temperature ranges.  We use a volt meter to carve up electrical voltages.

The point that I am making here, is that:

• measurement is the scientific way of carving up;
• our measuring systems are designed with a mathematical structure.

### What do we carve into?

With our normal perception, we carve the world into what we refer to as “things” or “objects”.  We carve into animals, plants, chairs, tables, rivers, etc.

Science (particularly physics) does it differently.  Physics carves the world into regions of space, periods of time, amounts of energy, etc.  In short, physics mainly carves the world into abstract objects.  If physics always seemed a little abstract to you, then you can now see why.

Physics also looks at smaller entities such as atoms and sub-atomic particles.  However, much of the study of these entities comes from looking at events rather than from carving into small entities.  The original idea for the Dalton atom came from examining the combinatorics of chemical reactions.  The original idea for the gene came from the combinatorics of inheritance, as studied by Mendel.  Scientists do have some ability to carve down to such small parts.  The double helix structure of DNA was discovered using X-ray crystallography, which can be considered a way of carving.  But most of what we know about subatomic particles comes from the study of events, usually interaction events.

Even when studying or theorizing about subatomic particles, physicists still use the measuring systems from classical physics.  So the carving into abstract entities has not gone away.

### The importance of standards

I want to emphasize here, how important it is to have standards.

I’ll start by looking at a digital camera.  The digital camera, in effect, carves up the world into small pixel-sized pieces, and measures the light intensity from each piece.

Suppose I take a picture.  And then I determine that pixel 371 had light intensity of 17.  Now I take another picture with the same camera.  But pixel 371 is pointing to a different part of the world.  So comparing intensities is useless.  A camera is good for generating pictures for human viewing.  But if we want to use it for science, and to compare pixel values, we have to very precisely control where it is pointing.

The camera example illustrates the problem when there are no standards.  Scientists have been pretty thorough in setting up standards to avoid this.  So there is a defined standard for the meter, used in measuring length.  There is a defined standard for time, based on the atomic clock.  And there are similar carefully defined standards for other scientific entities.

It is the use of these standards that allows us to compare data from different scientists.  In a way, it is this use of standards that allows us to see scientific observations as objective.  And it is because of the lack of such public in human perception, that we see perception as subjective.

Even back in my high school days, it seemed obvious to me that the efforts of the Newtonian scientists to standardize measurement, was a crucially important part of what made their science so effective.  Yet when I read books on philosophy of science, they rarely even mention the role of this standardization.

### Summary

I have connected the idea of carving up the world with that of measurement.  And I have presented an overview of how it is done in the sciences (particularly in physics).