Argument for Premise 1 of the First Way

Aquinas does not give an argument for the first premise, that change occurs, because he thinks it is obvious to the senses that it does in fact occur. This is the empirical premise of the argument. The original wording in the Summa is:

"It is certain, and evident to our senses, that in the world some things are in motion."

However, I will provide an argument for this as well, to supplement the empirical data. 

1. Change occurs at least at the level of consciousness (we experience change on a personal level)

2. Change does not occur (assumption for reductio

3. Therefore, change both occurs and does not occur (from 1, 2)

4. Therefore, it is not the case that change does not occur