Final answer:
The classical viewpoint's two main disadvantages include neglecting philosophical works' historical context and the difficult balance between Keynesian and Neoclassical economic models.
Step-by-step explanation:
The two main disadvantages of the classical viewpoint in philosophy and economics are seen in the tendency to either neglect the historicity of philosophers or the dual constraints in macroeconomic models. Firstly, focusing solely on philosophical arguments disregards the historical and cultural contexts in which a philosopher's work was conceived. This can lead to anachronistic interpretations and marginalization of different viewpoints.
Secondly, in economics, particularly in macroeconomics, the balancing act between the Keynesian and Neoclassical models can be likened to riding two horses at once, which highlights the strengths and weaknesses each model has to offer. While one represents short-term possibilities, the other deals with long-term implications, making it challenging to reconcile them for a comprehensive approach to economic policies.