‘Sed omnia praeclara tam difficilia quam rara sunt.
But all excellent [things] are as difficult as they are rare.’
This is the last sentence of Spinoza’s Ethics.
I’d always taken it, as I assume many other readers have, to mean simply that excellent things are both difficult and rare. The tam / quam construction of the sentence is a mere rhetorical flamboyance, found also in statements like: ‘Ah, Madame la Comtesse is as wise as she is beautiful!’ Such a statement, whatever the intentions of the speaker, is not intended to assert that the Countess’ wisdom is a function of her beauty. It simply states that her beauty and her wisdom are at the same level, whatever that might be.
Reading Spinoza’s statement in this way, I now see, doesn’t capture his intended sense. Clearly he did want to assert a kind of functional relation to hold between the difficulty and the rarity of excellent things. In writing the sentence, he was seeking to explain why so few people pursue the truly blessed life (as he conceived of it). An obvious answer is that blessedness, while excellent, is also difficult to attain. The final sentence explains this in terms of a general principle: excellent things are rare to the extent that they are difficult. This then draws its rhetorical force from an implicit assumption that excellent things are difficult to a very great extent, and thus, according to the stated principle, rare.
But this doesn’t seem to capture Spinoza’s meaning either. The example of the blessed life hardly suffices to show that excellent things in general are rare and difficult. I don’t think we have any business projecting the latter broad claim onto Spinoza. For one thing, it seems unduly pessimistic; are excellent things really so rare? Moreover, such a claim is in no way necessary to Spinoza’s purpose, which was simply to show that the rarity of the blessed life is to be explained by its difficulty of attainment. One could easily show that without speaking at all of the levels of rarity and difficulty of excellent things in general. Spinoza was not a philosopher to make sweeping assertions beyond what his express purposes demanded.
The problem is that we have so far taken the ‘omnia‘ in the sentence to quantify simply over excellent things. If the sentence’s subject is ‘excellent things in general’, then its implications can only be either that excellent things in general are rare and difficult or that they are not rare and accordingly not difficult. Either would amount to an excessively sweeping claim to project onto Spinoza.
The fact is that there is no clear indication in the sentence of what ‘omnia‘ is meant to quantify over. In Latin adjectives can be used substantively, which just means that the subject qualified by the adjective is left implicit. In this case ‘omnia praeclara‘ – ‘all excellent…’ is used substantively: the subject of the sentence is ‘all excellent X‘, where some plural noun should be substituted for X. But which noun that should be is left implicit. Thus far I have taken the implied missing noun to be ‘things’ (hence the insertion in square brackets in the quotation at the start). But this forces us towards the improbable claim that Spinoza meant to say that excellent things are, in general, both rare and difficult.
Here is my solution. We should take ‘omnia‘ to quantify over things falling under particular kinds rather than over things indiscriminately. Now Spinoza’s famous last sentence could mean that if some given kind is a kind of excellent things, then the things falling under it will either be easy and thus plentiful or they will be few because they are difficult. For the sentence to have this precise meaning, the implicit noun qualified by ‘omnia‘ would have to be rather complex – something like: ‘things falling under a kind such that the things falling under that kind are generally excellent’. Perhaps this is why Spinoza chose to leave it implicit.
At any rate, construing his meaning in this way allows that Spinoza is on one hand explaining the rarity of the blessed life in terms of its difficulty while on the other hand accepting that the world may be otherwise full of many excellent (though easy) things. ‘Blessed life’ is a kind of excellent thing; as such the fewness of its members is explained by their difficulty. But other kinds of excellent things may have many members that are not difficult.
What Spinoza is committed, nevertheless, to maintain is that if there is some kind whose members are both difficult and numerous, then it is not a kind of excellent things. It is easy enough to think of examples to support this judgment: the kind ‘academic journal articles’, for instance. It is not so easy to find examples of kinds of things that are not difficult but are rare. Spinoza is committed to saying that such kinds, also, cannot be kinds of excellent things. Perhaps he had his reasons.
Anyway, what this means is that the precise meaning of his sentence must be construed something like this:
‘But all things falling under a kind such that things falling under that kind are generally excellent are rare in proportion to their difficulty and as a result of their difficulty.’
It’s not beautiful, but I think it captures his intention pretty well.