“By freethinking I mean the use of the understanding in endeavoring to find out the meaning of any proposition whatsoever, in considering the nature of the evidence for or against, and in judging of it according to the seeming force or weakness of the evidence.”

What a shame that too many only believe themselves to think according to this description, while they do not really think much at all.

I believe he is referring to someone that has already opened the door, unfortunately most are unable to find the key.

He seems to only miss the boat by not explicitly listing the need to remove preconcieved assumptions from the process.

Force of evidence. Not force of emotion.

Everyone wants to be able to think freely, but few are comfortable with others' beliefs that are in opposition to their own.

Evidence, under the subject matters color or scope of use is to demonstrate, make as clear as possible, or ascertain a fact or point in issue. Certain evidence, such as circumstantial, is more often than not speculative at best, formed on biases, perceived through prejudices and filtered by pre-conceptions and opinions as is adverse to empirical data. Other types of evidence, such as primary, secondary, conclusive, direct, extrinsic, etc. have to also be measured to a high standard before becoming useful in determining truth. Depending on a most broad definition of evidence, there are also other determinants of discovering truth that may be equal to, or greater when understanding or endeavoring to find out the meaning of free thinking.

Reston, I agree, but everyone is subject to preconceived notions.

Left out : HONESTY !
... but beware: as my dad said, "Honesty IS 'the best policy,' but he who is honest BECAUSE it is 'the best policy' is not being honest."