In brief: For physics nothing; for the question what one’s own concepts actually do, a great deal. Hegel’s philosophy of nature is out of date; his logic is an investigation of how determinations such as force, law, cause, end, reciprocal action and measure work – and those are not out of date, because they are used in every laboratory.
First, the irritation out of the way
Yes, Hegel criticised Newton in a way that does not convince physicists. No, he did not claim that there could be only seven planets – that is a legend. And he said expressly that the philosophy of nature would not come about at all without empirical research:
Not only must philosophy be in agreement with the experience of nature; the emergence and formation of philosophical science has empirical physics for its presupposition and condition.
Encyclopaedia (1830), § 246 note
How much of the rest holds up is treated in the answer to Is Hegel’s philosophy of nature the Achilles heel of the system? In short: on evolution he rejects more than his procedure required; on self-limitation he keeps his word.
What is actually usable
The Science of Logic is not a doctrine of nature but an investigation of determinations of thought. Four passages are unusually rewarding for readers trained in the sciences:
– Quality, quantity, measure. Hegel’s thesis that quantitative change turns at certain nodal points into qualitative change is developed on states of aggregation and applies to everything now called a phase transition.
– Force and its expression. Hegel shows that a „force“ which is nothing beyond that in which it expresses itself supplies no explanation but a renaming – a critique of the explanatory tautology that ought to figure in every seminar on method.
– Law and appearance. The question in what sense a law of nature „exists“ is expressly put by him.
– End and mechanism. Whether teleology in biology is a manner of speaking or more has been disputed for two hundred years; Hegel’s version of the „inner end“ is one of the few attempts that do not settle the question by prohibition.
The point at which it really concerns natural science
§ 4 to § 7 of the Groundlines start from a presupposition with which natural science has a problem: that there is a will which determines itself. Hegel does not ground this on a gap in the causal chain – he holds the question „determined or free?“ to be wrongly put, because both answers understand freedom as arbitrary will (§ 15 note). Free, he says, is not the indeterminate will but the one that has itself as its content.
Whether that meets the debate on freedom of the will or passes it by, a reader trained in the sciences can judge better than most. It is at any rate no retreat into ignorance but a different question – and the place at which such a reader can test Hegel fastest.
A suggestion
One should not begin with the philosophy of nature but with § 1 to § 33, in which the conceptual apparatus is displayed – and watch what happens there methodically. To anyone who takes that for word-play Hegel has nothing to say. For anyone who recognises in it a reconstruction of what actually happens when a conceptual definition is set up, the rest repays the effort.
Sources. Encyclopaedia (1830), Part Two: Philosophy of Nature, §§ 245–251; Part One: Science of Logic, §§ 84–111 (being, quality, quantity, measure), §§ 136–141 (force and expression, law), §§ 204–212 (teleology). – Science of Logic I, first book, third section: Measure. – Groundlines § 4–§ 7, § 15 note. – In the glossary: The Science of Logic, Dialectic, The Understanding. – Literature. Michael John Petry (ed./trans.), Hegel’s Philosophy of Nature, 3 vols., London 1970; Terry Pinkard, Hegel’s Naturalism, Oxford 2012.