15.  Though one Man’s Idea of Blue should be different from another’s.

Neither would it carry any imputation of falsehood to our simple ideas, if by the different structure of our organs it were so ordered, that the same object should produce in several men’s minds different ideas at the same time; v.g. if the idea that a violet produced in one man’s mind by his eyes were the same that a marigold produced in another man’s, and vice versa.  For, since this could never be known, because one man’s mind could not pass into another man’s body, to perceive what appearances were produced by those organs; neither the ideas hereby, nor the names, would be at all confounded, or any falsehood be in either.  For all things that had the texture of a violet, producing constantly the idea that he called blue, and those which had the texture of a marigold, producing constantly the idea which he as constantly called yellow, whatever those appearances were in his mind; he would be able as regularly to distinguish things for his use by those appearances, and understand and signify those distinctions marked by the name blue and yellow, as if the appearances or ideas in his mind received from those two flowers were exactly the same with the ideas in other men’s minds.  I am nevertheless very apt to think that the sensible ideas produced by any object in different men’s minds, are most commonly very near and undiscernibly alike.  For which opinion, I think, there might be many reasons offered:  but that being besides my present business, I shall not trouble my reader with them; but only mind him, that the contrary supposition, if it could be proved, is of little use, either for the improvement of our knowledge, or conveniency of life, and so we need not trouble ourselves to examine it.

16.  Simple Ideas can none of them be false in respect of real existence.

From what has been said concerning our simple ideas, I think it evident that our simple ideas can none of them be false in respect of things existing without us.  For the truth of these appearances or perceptions in our minds consisting, as has been said, only in their being answerable to the powers in external objects to produce by our senses such appearances in us, and each of them being in the mind such as it is, suitable to the power that produced it, and which alone it represents, it cannot upon that account, or as referred to such a pattern, be false.  Blue and yellow, bitter or sweet, can never be false ideas:  these perceptions in the mind are just such as they are there, answering the powers appointed by God to produce them; and so are truly what they are, and are intended to be.  Indeed the names may be misapplied, but that in this respect makes no falsehood in the ideas; as if a man ignorant in the English tongue should call purple scarlet.

17.  Secondly, Modes not false cannot be false in reference to essences of things.