True, if the assumptions are true. But not science.
One of your premises is wrong. You would have made a better argument if you had said:
(1) All winged animals can fly.
(2) Ostriches have wings.
(3) Therefore, ostriches can fly.
You would have proved your point -- that symbolic logic is not scientific -- by using accurate premises. No need to invent winged horses.
You misunderstood my point. My point was not that symbolic logic is not scientific. On the contrary, symbolic logic is a useful tool. My point was that if a premise is wrong, the conclusion is wrong. Thus, I deliberately used an inaccurate premise (Horses have wings) - to illustrate the point - that the tool, symbolic logic, will lead one astray if it is used incorrectly. Garbage in, garbage out.