Theme 1: Theory of science

Sense-data

Russell introduces the term sense-data when he presents the example of human perception of physical objects, in the form of a table. There he makes the point that our perception of the table relies on our different immediate sensations. These sensations are things such as colours, sounds, smells etc. The term sense-data is therefore introduced as an attempt to explain that each and everyone of us has an unique perception of what a specific object is and what it looks like. The immediate sense-data for a deaf and colour blind person may probably be different from a hearing person with sunglasses. The object is therefore not absolute, but relative and subjective to the beholder and relies on his or her sense data. This also makes Russell question if the physical object (or “matter”) even exists, as it may “just” be based on our senses and impressions.

Proposition and Statement of fact 

As far as I understand the gist of Russells text correctly, he argues that the terms “proposition” and “statement of fact” are descriptive expressions of reality with a certain degree of truth to them. At least that may be the key connotations of them. However, what separates the two is that the latter possess a greater “truth value”. 

When you talk about a “truth value” in this context, it refers to the general belief - the consensus - of people. You can therefore describe a preposition to be (according to Russell but in my own words) something you believe from a certain acquaintance to matter or ideas, based on your sense- or historical data. A statement of fact is, however, a proposition that possess a widespread consensus. This can be achieved by performing real life “testing” of the proposition.

Definite descriptions 

According to Russel, a “definite description” is a term used for something that is determined and singular. This is contrary to the term which he calls “ambiguous description”, which is undetermined. He exemplifies this by bringing up the phrase “a man” as an example of an ambiguous description, whilst “the man with the iron mask” in this case is an example of a definite description. I would myself however argue that definite descriptions (the so-and-so) can still possess a certain degree of ambiguousness as there might be different connotations for “the man with the iron mask” for different people, depending on their experiences. Perhaps the term “indefinite description” would be less ambiguous than the term “ambiguous description”.

Knowledge 

Russell talks about knowledge in a broad sense, but argues that there are, predominantly, two ways in which something may be known: by means of a description and judgement (in which one or several parts are judged to be related as they are in fact related) or by means of acquaintance (which comprises one’s perception and experience). He therefore states that “true belief” does not constitute what is the consensus of the meaning of the word “knowledge”. A “true belief” will always be a belief, no matter how much “truth” it possess. 

Furthermore, he talks about the “nature” of a thing, which he argues has the meaning of “all the truths about the thing”. This further spurs on that knowledge is relative and that possessing an acquaintance of a thing does not necessarily mean that you possess much knowledge about the thing, or hardly anything about the “nature” of the thing. You need to know how the thing relates to its reality. He gives the example of him visiting a dentist. Even though he is acquainted with his own toothache and his dentist is not, the dentist still possess greater knowledge about the nature of the toothache than the patient himself.