It seems quite unreasonable to assume that far away stars that have no connection between them, but that seen from the earth reminded old Greek fellows of some mythical figures, influence our personality. Of course, everything is connected and so there could be an influence, though, how it works would be impossible to be explained.
However, where old Greek fellows saw Capricorn rising in the end of December, today there is not Capricorn rising anymore, because of all the movements of the Earth, the solar system, the Galax (I didn't grasp the Physics of that part), the constellations now rise almost one month later than they did 2000 years ago.
So if someone has Capricorn as its sun sign, actually the constellation in the night sky when he was born was not Capricorn.
Does this mean astrology is fake and we should burry it immediately and forever?
No. In fact, what matters is not at all the constellation rising at the time of your birth, but the position that the Earth has in relation to the Sun. The Earth moves around the Sun in one year, and that circle of 360' has been divided into 12 equal parts to which the symbols of the constellations have been attributed some 2000 years ago.
Now, the influence of the position of the Earth around the Sun is obvious, as it is revealed in the seasons. But it has also other influences, for example, on crystallization processes, as Lilly Kolisko has shown in the early 20th century.
But wouldn't it be boring to say, I was born at 274', instead of saying "I'm Pisces" or so? Though, that would certainly suit our modern mathematical and materialistic minds much more.
Why the time of birth should imprint personality traits upon us nevertheless remains enigmatic. Hum, I start to guess that it is not time of birth that really matters...