Could you help me understand this English passage? ?

What does the last sentence "the scientist is rightly not impressed by the age of an idea" mean?  Science constantly changes. Its findings are never true in an absolute now-and-forever sense; they are always provisional and can always be improved. The convincing orthdoxy of one century becomes the... show more What does the last sentence "the scientist is rightly not impressed by the age of an idea" mean? 

Science constantly changes. Its findings are never true in an absolute now-and-forever sense; they are always provisional and can always be improved. The convincing orthdoxy of one century becomes the historical curiosity of the next. It is a little awkward to say that science makes progress, because we do not know where we are going, but we certainly know where we have been and can thus talk about science gradually moving away from error. Again we can see the point if we contrast the reliance of medical science on experimental proof with the reliance of alternative therapies on tradition. In the world of Bachian flower remedies, Feng Sui and Shiatsu massage, that something has been done for centuries (preferably in a culture untainted by modernity) establishes its validity. Given that such fundamentals of medical science as the body's circulatory system are relatively recent discoveries, the scientists is rightly not impressed by the age of an idea. 
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