Is Hilary Putnam's Argument To Refute The BIV?

VII.II.I. Hilary Putnam’s Response to the BIV
Admittedly, there is one famous objection to the BIV that would be an injustice to ignore: Hilary Putnam’s argument from semantic externalism. Semantic externalism, as defined by the Stanford Encyclopedia of Philosophy, is “the thesis that the meaning and reference of some of the words we are not solely determined by the ideas we associate with them or by our internal physical state.” In his Reason, Truth and History Putnam argues that the BIV scenario is conceptually impossible. Put concisely, his reasoning is as follows: to say that “I am a brain-in-a-vat” is self-refuting. Brains-in-vats have never encountered any external things; thus, it is impossible for them to correlate the words in such
Harrison offers two substantial objections to Putnam’s position that I find to be plausible. First, he suggests that the argument is a fallacy. For example, in a world which by the term “round” everyone really meant “flat,” it would technically be false that the world is round. However, the world would remain round regardless of whatever people meant by the word “round;” Therefore, he thinks, the use of words should not have “effects of such cosmic proportions.” If, for instance, people considered the word “round” to mean what we consider the definition of “flat,” the claim that “the earth is round” would be false. In the world we know, however, the claim “the earth is round” is true. As Harrison then illustrates, this can be applied to Putnam’s argument: in a world where we were truly all brains-in-vats, and “brain” meant “brain-image” and “vat” meant “vat image,” the people (the brains-in-vats) in such a world would really mean “I am a brain image in a vat image” when they utter “I am a brain in a vat.” Thus, Harrison contends, Putnam’s conclusion is incorrect. Instead, if everyone was truly a brain-in-a-vat, then nobody could use the claim “I am a brain in a vat” to express the fact that they are truly a
If this were the case, then in taking a person who was originally a brain-in-a-vat and placing them in the real world, that person would have the ability to successfully signify what we consider to be a building with the word “building.” Put another way, if one sees a giraffe on television (let us say this is their first time witnessing the concept of a giraffe), then they are technically seeing an “image-of-a-giraffe.” However, even if the only knowledge that person has about giraffes is what they know from the television program (the image-of-a-giraffe), they could still successfully identify a giraffe in the real world. It is reasons like this, Harrison claims, that “when we have a hallucination, we do not usually know we are having one.” Thus, Putnam’s objection to the BIV skepticism is problematic; or at the very least