In my previous entry, I attempts to define “objective” and “subjective” using the dictionary, as this would convey the common meaning of those words.

I defined objective knowledge as “unbiased knowledge about the world around us” and subjective knowledge as “that which exists in the mind and pertains to the one who holds the knowledge.”

The problems with these definitions are as follows:

1. All knowledge exists in the mind.

2. It is not clear that unbiased knowledge exists, and even if it did, it would constitute a tiny fraction of our knowledge.

3. Whether or not knowledge is biased is not relevant to its validity. If I hated cats, for example, that would not invalidate my subjective claim that cats tend to scratch up furniture.

4. Subjective claims are often about the world around us. For example, if I claimed that President Bush was the worst president in US history, this is a truth claim about President Bush and US history.

So we need something better that these dictionary definitions. Let me thus propose something that George Cooper offered on the ASA list:

Could we not simplify define “objective” as being that which can be measured by all parties who should obtain the same result given an appropriate range of accuracy?

Measurement is thus the key to objective knowledge. And it has to be a form of measurement whereby everyone would get basically the same result. And this explains why we tend to associate science with objectivity, as science is built around instruments that measure as part of an experimental design.