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1.3 Objections

An objection is like a reason, but is evidence against a contention. 

Consider the following passage from Apollo Moon Landings:

There are no stars in the background of the Apollo pictures.  Therefore, Apollo astronauts did not land on the Moon. (3.0-1)

Here, we are given evidence against the idea that Apollo astronauts landed on the Moon. 

The contention is that Apollo astronauts landed on the Moon; the evidence (which goes against it) is that there are no stars in the background of the Apollo pictures.

Here is a map of the reasoning, showing the objection in red:

Here is another example:

It is not true that there should be lots of stars in the Apollo pictures, because stars can be very faint.

The contention (the thing being objected to) is that there should be lots of stars in the Apollo pictures; the evidence is that stars can be very faint. 

Objections and reasons are very similar; it is just that while reasons present evidence supporting the contention, objections present evidence against it. Roughly, an objection "says why the contention wouldn't be true."

You may have noticed that a reason can be transformed into an objection, and vice versa, if you reverse the contention.

In the mapping approach used here, we show that something is an objection by the use of (a) the colour red, for objection; and (b) the word "but" just above the objection.

Technically, an objection is, like a reason, really a set of claims.  This will become more clear in Tutorial 2.

An objection is a piece of evidence against some claim.  Technically, an objection is set of claims working together to provide evidence that another claim is false.