Discrepancy between Tae Kim's Guide and Tobira in regards to 思われる。

Question

I'm just wondering if someone could help me with what seems to be a difference between Tae Kim's Guide and what I've read in Tobira. In grammar point 2 from chapter 4 in Tobira, it says that "考えられている usually indicates an opinion arrived through logic" and "思われている usually indicates an opinion derived from intuition", and that these two are used to introduce a "generally-accepted opinion." Further, it indicates that 考えられる and 思われる "indicated the speaker's/writer's opinion". Which brings me to Tae Kim's. On his page about Causative and Passive Verbs the following sentence is found: 光の速さを超えるのは、不可能だと思われる。(Exceeding the speed of light is thought to be impossible. ) This looks like it is referring to a generally-accepted opinion, and one that was derived through logic, but it is using 思われる, meaning that it is suggesting virtually the opposite of what is said in Tobira. I'm much more inclined to trust Tobira on this, but I wanted to ask this question because there may be something I'm not understanding here.

Answer 1

Your confusion is legit, because "opinion" and "intuition" aren't easily applicable words when talking about something scientific (physics), so allow me to try to differentiate the nuances in this case:

光の速さを超えるのは、不可能だと思われる。

Exceeding the speed of light is thought to be impossible.

This expression suggests that light speed cannot be exceeded, but that the door is open for more experiments that may one day prove/disprove this possibility.

光の速さを超えるのは、不可能だと考えられている。

Exceeding the speed of light is thought to be impossible.

This expression suggests that light speed cannot be exceeded, a conclusion made from of past experiments and deductions.