It is a question of fact, whether the influence of motives be fixed by laws of nature, so that they shall always have the same effect in the same circumstances.
Thomas ReidIn every case, we ought to act that part towards another, which we would judge to be right in him to act toward us, if we were in his circumstances and he in ours; or more generally - What we approve in others, that we ought to practise in like circumstances, what we condemn in others we ought not to do.
Thomas ReidIt appears evident, therefore, that those actions only can truly be called virtuous, and deserving of moral approbation, which the agent believed to be right, and to which he was influenced, more or less, by that belief.
Thomas ReidIn every chain of reasoning, the evidence of the last conclusion can be no greater than that of the weakest link of the chain, whatever may be the strength of the rest.
Thomas Reid