[busyboy]

Thoughts are not necessary for existence.

[tsimionescu]

"Because I think, I am" implies more that existence is necessary for thoughts, which is true. If you didn't exist, you couldn't think.

[busyboy]

"Because I think, I am" just implies that I exist because I think. This implies that thoughts are a necessity for existence. I am saying that is not the case and thoughts are not a necessity for existence. What you inferred, although true, is not the correct implication of the statement.