The thinking is "soul" (lifeforce)
The WT explanation makes zero sense. They just don't want people believing that they will be conscious after they die. That idea might cause people to dig a little deeper than the pages of a WT rag.
Think about it: Dead souls of believers that are killed during the Great Tribulation end up in heaven, thinking, remembering, talking etc. That's a lot more than a "life force"!
Rev. 6 -
And when he had opened the fifth seal, I saw under the altar the souls of them that were slain for the word of God, and for the testimony which they held:
10 And they cried with a loud voice, saying, How long, O Lord, holy and true, dost thou not judge and avenge our blood on them that dwell on the earth?
11 And white robes were given unto every one of them; and it was said unto them, that they should rest yet for a little season, until their fellowservants also and their brethren, that should be killed as they were, should be fulfilled.
Now the WT can't have dead souls in heaven can they? Why, because JW's supposedly don't go to heaven. And, we can't have JW's wondering where they will be conscious after death if they are not in heaven can we?